Nanocrystalline Cellulose: Green, Multifunctional and ... · Nanocrystalline Cellulose: Green, Multifunctional and Sustainable ... 524 Handbook of Composites from Renewable ... Treated

523

Vijay Kumar Thakur, Manju Kumari Thakur and Michael R. Kessler (eds.), Handbook of Composites from Renewable Materials, Volume 7, (523–556) © 2017 Scrivener Publishing LLC

*Corresponding author: [email protected]

17

Nanocrystalline Cellulose: Green, Multifunctional and Sustainable Nanomaterials

Samira Bagheri, Nurhidayatullaili Muhd Julkapli* and Negar Mansouri

Nanotechnology & Catalysis Research Centre (NANOCAT), IPS Building, University Malaya, 50603 Kuala Lumpur, Malaysia

AbstractThis chapter is divided into three sections: the first section briefly discusses the properties of nanocelluloseand it is followed by a section reviewing the progress to date of functionalized nano-cellulose. The last section discusses the applications of functionalized nanocellulose for specific and high-performance purposes. The resulting functionalized nanocellulose products with nano-sized dimensions and excellent physical properties which, combined with their edo-friendliness and their bio-degradability, make them materials of choice in the promising area of bionanotech-nology, opening up major commercial markets and consistent with the green chemistry trend.

Keywords: Nanoparticles, grafting, dispersion, homogeneity, renewable bioresources

17.1 Introduction: Natural Based Products

During the past decades, massive efforts have been made to improve new materials and replace widely used oil-based products by utilizing biorenewable resources (Fattori et al., 2011; Gómez-Guillén et al., 2009; Olivetti, Gaustad, Field, & Kirchain, 2011: Thakur et al., 2013a–f). Therefore, there is an increasing demand for products made from renewable, nontoxicity, biodegradability, and renewability in the coming decades, as well as sustainable nonpetroleum-based resources (Fattori et al., 2011; Singha & Thakur, 2010a–c). Along with the enhancements in processing plant materials, includ-ing cellulose, lignin, starch, and hemicellulose these let the forecast that more and more everyday products will completely or partially composed of biodegradable and biore-newable sources (Chauhan, Mahajan, & Guleria, 2000; Shaabani, Rahmati, & Badri, 2008; Walther, Timonen, Díez, Laukkanen, & Ikkala, 2011; Thakur & Voicu, 2016). From the aforementioned plant material, particularly the cellulose and hemicellulose have promising features, including high abundance and existing refining factories (Chauhan et al., 2000; Thakur et al. 2014a–d)). In addition, utilize of cellulose-based materials do not raise ethical concerns since they cannot be utilized as food, which makes them promising in comparison with starch (Shaabani et al., 2008).

524 Handbook of Composites from Renewable Materials-Volume 7

17.2 Nanocellulose

The cellulose is a linear polysaccharide consisting of b-1,4 connected glucopyranose units, along with chains of polymer associated by hydrogen bonds forming fibrils bun-dles that contain highly ordered crystalline as well as disordered amorphous domains (Chauhan et al., 2000). The crystalline domains further isolated in nano-scale with reg-ular rod-like and highly ordered nanocrystals, after acid hydrolysis and removing the amorphous regions, which is called cellulose nanofibers, crystalline nanowhiskers, or nanocellulose (Morán, Alvarez, Cyras, & Vázquez, 2008). Nanocellulose obtained from various sources, including algae, sea animal (tunicate), and plant biomass. It also can be produced by biosynthesis by some bacteria known as bacterial cellulose or microbial cellulose (Gardner, Oporto, Mills, & Samir, 2008).

As natural nano-scaled material, nanocellulose possesses diverse characteristics different from traditional materials, including special morphology and geometrical dimensions, crystallinity, high specific surface area, rheological properties, liquid crys-talline behavior, alignment and orientation, mechanical reinforcement, barrier prop-erties, surface chemical reactivity, biocompatibility, biodegradability, lack of toxicity, and others (Figure 17.1) (Jin et al., 2011; Korhonen, Kettunen, Ras, & Ikkala, 2011; Lee et al., 2009). Such benefits of nanocellulose are chiefly caused by its high stiffness and strength combined with low weight, as well as its renewability, biocompatibility, and biodegradability (Korhonen, Kettunen, et al., 2011).

17.2.1 Nanocellulose: Properties

The nanocellulose can be obtained via two approaches: bottom-up by biosynthesis or top-down by disintegration of plant materials (Table 17.1). On top-down approach, the production of nanocellulose chemically induced via destructing strategy of amorphous region and preservation of highly crystalline structure (Malho, Laaksonen, Walther,

Source of cellulose Pretreatments

Nanocellulose synthesisNanocellulose applications

Alkali treatmentWaste water treatmentBiomedical applicationCatalysis

Acid hydrolysisMechanical treatment

Fibrillation

Chemical processChemical processPhysical processEnzymatic process

Physical processEnzymatic process

Agricultural residuesWood, PlantsBacteria, Algae

Figure 17.1 General sources, properties, and application of nanocellulose.

Nanocrystalline Cellulose 525

Table 17.1 Synthesis route of nanocellulose.

Synthesis routeFeeding

materials Properties Applications ReferencesBottom-up

biosynthesisFermentation of

low-molecular weight sugars using bac-teria from Acetobacter species

Termed as bacte-rial cellulose

Inherently nano-sized ribbon shaped cel-lulose fibrils

Largest dimension ranging from 25 to 86 nm

Length up to several micrometers

High critical sur-face energy

Tissue engineering

Biomedical engineering

Advanced fiber composites

(Malho et al., 2012; Wu et al., 2012)

Top-down disintegra tion of plant materials

Treated natural fibers with strong ultra-sound to dis-integrate larger bundles of natural fibers into smaller elementary fibrils whilst retaining the fibrous texture

Using high-pressure homogenizer to reduce the size of wood fibers down to nanometer scale

Nanocellulose with organized in extended chain confor-mation with a high degree of long range order

Diameter of 5–30 nm, length of 100–500 nm or length of 100 nm to several micrometer

The morphology and dimension assessed as elongated rod-like nanopar-ticles and each rod could be regarded as a rigid cellulosic crystal without apparent defect

(Aulin et al., 2012; Korhonen, Hiekkataipale, et al., 2011)

Ikkala, & Linder, 2012; Wu, Saito, Fujisawa, Fukuzumi, & Isogai, 2012). The chemi-cal and/or mechanical destruction applied, which involves acid hydrolysis, enzymatic treatment, high-pressure homogenization, and grinding (Aulin, Salazar-Alvarez, & Lindström, 2012; Korhonen, Hiekkataipale, et al., 2011).


These synthesis routes of nanocellulose produced three different types of nanocel-lulose (i) cellulose nanocrystals (CNCs) with another designation, including nano-crystalline cellulose, cellulose (nano) whiskers, and rod-like cellulose microcrystal; (ii) cellulose nanofibrils (CNFs), with the synonyms of nanofibrillated cellulose, micro-fibrillated cellulose, cellulose nanofibers; and (iii) bacterial cellulose, also referred to as microbial cellulose (Table 17.2) (Figure 17.2).

17.2.1.1 Nanocellulose: Mechanical Properties

One of the main driven for utilizing nanocellulose is the possibility to exploit the stiff-ness and strength of cellulose crystal. In general, the mechanical properties of nano-cellulose characterized by its features in both the ordered crystalline domains and disordered amorphous regions of the nanoparticles (Jonoobi, Harun, Mathew, Hussein, et al., 2010). Cellulosic chains in disordered regions contribute to the plasticity and flexibility of the bulk material, but those in other domains contributing to the stiffness and elasticity of the material. The modulus of different types of nanocellulose expected to result from a mixing rule between the modulus of the crystalline domains and the amorphous fraction (Cervin, Aulin, Larsson, & Wågberg, 2012; Mihranyan, Esmaeili, Razaq, Alexeichik, & Lindström, 2012).

Although it is challenging to determine the true modulus and strength of cellulose crystals, theoretical calculations, and numerical simulations used to estimate the axial modulus of cellulose crystal to be approximately 58–180 GPa, which gives specific val-ues similar to Kevlar (60–125 GPa) and potentially stronger than steel (200–220 GPa) (Table 17.3).

As for the tensile strength of nanocellulose concerned, theoretical predictions indi-cate that it has a tensile strength in the range 0.3–22 GPa. The predicted high tensile strength of nanocellulose is due to the extended chain conformation of crystalline cel-lulose, high density of covalent bonds per cross-sectional area, and the large number of inter- and intramolecular hydrogen-bonding sites (W. Hamad, 2006; Xiong, Zhang, Tian, Zhou, & Lu, 2012).

17.2.1.2 Nanocellulose: Physical Properties

In general, b-1,4-anhydro-d-glucopyranose units in nanocellulose structure do not lie precisely in the plane but rather assume a chair conformation with sequential glucose residue rotated through the 180° angle. Another important characteristic of nanocel-lulose is that three hydroxyl groups of each glucose unit, which endows nanocellulose a reactive surface covered with numerous OH groups (Bai, Holbery, & Li, 2009; Xiong et al., 2012). The capability of these OH groups to form hydrogen bonds has a key role in the fibrillar formation and semicrystalline packing, which controls the essential physical features of this highly cohesive nanomaterial (Figure 17.3) (Zhou & Wu, 2012). It reported that on the structure of nanocellulose, the OH groups at the 6-carbon posi-tion react 10 times faster than the other OH groups, while the reactivity of the hydroxyl group of the 2 carbon position found to be twice than that of at the carbon 3 position (Shopsowitz, Hamad, & MacLachlan, 2011).


Table 17.2 Nanocellulose derivatives and its properties.

Nanocellulose derivatives

Synthesis method

Morphological structure Particle size References

Nanocrystalline cellulose

Chemically induced restructuring such as acid hydrolysis via the removal of amorphous regions and preservation of highly crystal-line structure

Elongated rod-like/needle like nanoparticles

each rod can be regarded as a rigid cellulose crystal with-out apparent defect

54–88% crystal-line region

Diameter of 5–30 nm, length of 100–500 nm or length of 100 nm to several micrometer

(Cranston & Gray, 2006; Peng, Dhar, Liu, & Tam, 2011)

Nanofibril cellulose

High-pressure homogeniza-tion and/or grinding before and/or after enzymatic or chemical treatment

Multiple mechan-ical shearing action effec-tively delami-nate individual microfibrils from cellulosic fibers

Consist of both individual and aggre-gated nano-fibrils made of alternating crystalline and amor-phous cellu-lose domains

Entanglement of softness and long chains

Fibril width from 10 to 100 nm depending on the source of cellulose, defibrillation process, and pretreatment

(Jonoobi, Harun, Mathew, Hussein, & Oksman, 2010; Leitner, Hinterstoisser, Wastyn, Keckes, & Gindl, 2007)

Bacterial cellulose

Biosynthesis process from tiny unit (Å) to small unit (nm) by bacteria (such as Acetobacter xylinum) in pure form

Glucose chains produced inside the bac-terial body and extruded out through tiny pores present on cell envelope

With the combi-nation of glu-cose chains, microfibrils formed and further aggregate as ribbons (nanofibers) and generate a web-shaped network structure with cellulosic fibers

Diameter of 20–100 nm with different types of nano-fiber network

(Nakagaito, Iwamoto, & Yano, 2005; Soykeabkaew, Sian, Gea, Nishino, & Peijs, 2009)


Table 17.3 Predicted Young Modulus of nanocellulose derived from different mechanical testing.

Nanocellulose derivatives Testing methods

Young modulus (GPa) References


Atomization stimulation using both standard uniform deformation and a complementary approaches based on nanoscale indentation

139.5 ± 3.5 (Dagang Liu, Chen, Yue, Chen, & Wu, 2011)


Atomic structure model of cellulose in tandem with quantum mechanics

206 (Zhang, Elder, Pu, & Ragauskas, 2007)

Nanofibrile cellulose

Longitudinal modulus of cellulose 100 (Olsson et al., 2010)

Nanofibrile cellulose

Three points bending experiment using atomic force microscopy tips

81 ± 12 (Ahola, Österberg, & Laine, 2008)

Bacterial Cellulose

The Raman spectroscopic technique involved determination of local molecular deformation via a shift in the central position

114 (Nimeskern et al., 2013)

H

Hydrogen bonding within andbetween cellulose molecules

Cellulosemicro�brils

Amorphous region Crystalline region Amorphous region

OO

O OHO

OHHO

HO O O

HO OH

HO OH O

OHO

HOOHHO

OO

HO O O

HO OH

O

OH

OH

OO

HO

OH

OOH

OHO

HO

OH

Figure 17.3 The crystalline and amorphous region of nanocellulose (Zhou & Wu, 2012).

Plant (wood, cotton etc.) Plant cellulose pulp

Re�ning andhomogenization

Chamical andmechanical

isolated

Micro�bril ornano�bril

Acidhydrolyzation

NCC or CNCMFCs or NFCs

Pulping

Figure 17.2 Product derivatives of nanocellulose.


17.2.1.3 Nanocellulose: Surface Chemistry Properties

One of important surface chemistry characteristics of nanocellulose is the surface charges, which mainly refer to negative sulfate esters (–OSO3

−). Surface sulfate esters introduced on nanocellulose during sulfuric acid hydrolysis through condensation esterification (sulfation) between surface OH and a H2SO4 molecule, using another H2SO4 molecule as a condensation agent (Beck, Bouchard, & Berry, 2010; Hamad & Hu, 2010). The H2SO4 hydrolyzed nanocellulose therefore highly negatively charged and form a highly dispersed colloidal suspension in water. The surface charge amount of sulfate groups on nanocellulose can be controlled through the duration and tem-perature of HSO4 hydrolysis (Brinchi, Cotana, Fortunati, & Kenny, 2013). Moreover, the promotion of the nanocellulose high stability in solvents, the surface of –OSO3− groups with negative charges also provide nanocellulose the accessibility for biomedical application, including as electrostatic adsorption of enzyme or protein (Li, Wang, & Liu, 2011).

17.2.2 Nanocellulose: Synthesis Process

17.2.2.1 Conventional Acid Hydrolysis Process

A controlled strong acid hydrolysis treatment applied to cellulosic fibers allowing the dissolution of amorphous domains and therefore longitudinal cutting of the microfi-brils. In the acid hydrolysis process, the hydronium ions enter the amorphous domains cellulose chains promoting the hydrolytic cleavage of the glycosidic bonds and releas-ing individual crystallites after mechanical treatment (sonication) (Figure 17.4).

String acid hydrolysis of pure cellulosic material under strictly controlledconditions of temperature, time, agitation and with control of other

conditions such as nature and concentration of the acid and the acid tocellulose ratio

Dilution with water to stop reaction and repeated with successivecentrifugation

Extensive dialysis against distilled water to fully remove free acidmolecules

Mechanical treatment, usually sonication to disperse the nanocrystal asa uniform stable suspension

Eventual concentration and drying of the suspension to yield solidnanocellulose

Figure 17.4 Typical procedure for the production of nanocellulose.


Diverse strong acids have presented to successfully degrade cellulose fibers and for that HCl and H2SO4 have extensively used (Bondeson, Mathew, & Oksman, 2006; Li et al., 2011). However, H2PO4, HBr, and HNO3 have also reported for the preparation of nanocellulose. Indeed, most of the research works using H2SO4 as a hydrolyzing agent due to the surface OH groups through an esterification process allowing the grafting of anionic sulfate ester groups (Elazzouzi-Hafraoui et al., 2007). The existence of negatively charged groups persuades the formation of the negative electrostatic layer, which covering the nanocellulose as well as promote its dispersion in the water media (Lu & Hsieh, 2010; Zhao et al., 2007). The sulfation has a key role in defin-ing the yield of extracted nanocellulose and imparting nanocellulose features such as degree of polymerization and crystallinity. An interesting investigation reviewed that at longer hydrolysis times, shorter nanocellulose with narrow polydispersity pro-duced (Wang, Ding, & Cheng, 2008). However, as the cleaving of cellulose chains, during the acid hydrolysis, happened accidentally and the dimension of nanocellulose is not homogeneous and uniform. Therefore, some research approach has focused on suing catalytic conversion of nanocellulose (Filson & Dawson-Andoh, 2009; Rosa et al., 2010).

17.2.3 Nanocellulose: Limitations

17.2.3.1 Single Particles Dispersion

The foremost challenge with nanocellulose connected to their homogeneous disper-sion within any medium and matrix (Beck, Bouchard, & Berry, 2012; Boluk, Zhao, & Incani, 2012; Viet, Beck-Candanedo, & Gray, 2007). Moreover, nanocellulose has a strong propensity for self-association due to the omnipresence of the surface interact-ing of OH groups (Boluk et al., 2012). These inter-particle interactions, in the prepa-ration of single particle-dispersed nanocellulose, cause agglomeration and limit the potential of mechanical, thermal, and conductivity properties. Indeed, the electro-static forces effect colloidal stability, making suspension of nanocellulose sensitive to the ionic strength of the medium (Ma, Zhou, Li, Li, & Ou, 2011). This phenomenon magnified when the size of nanocellulose particle reduced. Nanocellulose functional-ization is of interest to enhance compatibility with a wider medium and matrix diver-sity (Kalashnikova, Bizot, Cathala, & Capron, 2011; Male, Leung, Montes, Kamen, & Luong, 2012).

17.2.3.2 Barrier Properties

There is a growing barrier in properties of the nanocellulose-based products due to increased tortuosity provided by the nanocellulose particles (Fortunati et al., 2012; Siqueira, Bras, & Dufresne, 2010; Yang, Tejado, Alam, Antal, & van de Ven, 2012). Certainly, due to the small size, the surface-to-volume ratio of nanocellulose is expres-sively superior in comparison with microparticles (Abitbol, Johnstone, Quinn, & Gray, 2011). Provided that strong particle–particle interactions exist, a greater ability to bond to the surrounding medium is for smaller particles, thus reducing the chain segmental mobility and accordingly the penetrant diffusion (Paralikar, Simonsen, & Lombardi, 2008).


17.2.3.3 Permeability Properties

Nanocellulose is a hydrophilic material and it obviously absorbs water when immersed in liquid water or conditioned in moist atmosphere (Kaboorani et al., 2012). This water vapor permeability is significantly decreased when nanoclellulose disintegrated to nano-scale level. The gas permeability is also reduced in dry atmospheres when decreasing the size of the nanocellulose particles because of the crystalline and dense structure of nanoparticles (Feese, Sadeghifar, Gracz, Argyropoulos, & Ghiladi, 2011; Satyamurthy, Jain, Balasubramanya, & Vigneshwaran, 2011). However, this property is lost in moist atmosphere.

17.3 Nanocellulose: Chemical Functionalization

The functionalization of nanocellulose has obtained much attention because of the pro-found enhancement of properties, including increased mechanical and reduced gas bar-rier features (Lam, Male, Chong, Leung, & Luong, 2012; Pei, Zhou, & Berglund, 2010; Rebouillat & Pla, 2013). Besides, stable nanocellulose dispersion in a polar or low polar-ity solvent gained via physically coating the surface by using the surfactant or chemical grafting apolar moieties onto the surface (Figure 17.5) (Rebouillat & Pla, 2013). The functionalized nanocellulose can be dispersed in low polarity organic liquids and mixed with matrix solution. It allows an improvement in the dispersion of the functionalized nanocellulose in the continuous apolar medium, which is favorable for optimizing the final application of nanocellulose. However, it limits the interactions between nanocellu-lose particles through hydrogen bonding which is the reason for the excellent dispersion features of nanocellulose (Filpponen & Argyropoulos, 2010; Siqueira, Bras, & Dufresne, 2008). The nanocellulose surface functionalization includes the plenty surface OH groups resulting from their nano-scale dimensions and ensuing high specific surface area. Most of the surface functionalization experimental process is done in mild conditions. This is to preserve the integrity of the nanoparticles and peeling effect of surface-grafted chain

ONa

Cell-C=O

TEMPO-Media oxydation

Cell-O-PolymerPolymergrafting

Silylation

Cell-O-Si-R

Esteri�cation

Cationization

Fluorescentlabelling

Cell-O-FITC

Cell-OH

CH3

CH3

CH3

Cell-O-C=O

Cell-O-Cat*,An

Figure 17.5 Route map on surface functionalization of nanocellulose (Rebouillat & Pla, 2013).


that induced the dissolution in the reaction media. (Braun & Dorgan, 2008; Cranston, Gray, & Rutland, 2010; Kloser & Gray, 2010; Tingaut, Zimmermann, & Sèbe, 2012) The surface functionalization of nanocellulose categorized into two main groups, namely organic and inorganic compounds (Tingaut et al., 2012).

The key concern with the nanocellulose functionalization would be to carry out the procedure to the extent which it only modifications the nanocellulose surface, although conserving the initial morphology to prevent any kind of polymorphic conversion and conserve the crystal integrity (Niederberger et al., 2004; Pahimanolis et al., 2011; Song & Sailor, 1998).

17.3.1 Organic Compounds Functionalization

The purpose of nanocellulose surface functionalization with organic compounds typi-cally to improve compatibility with polar matrix, consequently to increase the dispers-ibility and functionality of nanocellulose particularly when utilized in combination with hydrophobic or nonpolar matrices (Lahiji et al., 2010; Rueda et al., 2011; Zaman, Xiao, Chibante, & Ni, 2012). This can be achieved by introducing of highly stable posi-tive or negative electrostatic charges on the nanocellulose surface (Yang et al., 2005).

17.3.1.1 Molecular Functionalization

In general, molecular functionalization involves the substitution of OH groups with small molecules, grafting onto strategy with different coupling agents and grafting from approach with a radical polymerization involving ring-opening polymerization, atom transfer radical, and single electron transfer-living radical polymerization (Biyani, Foster, & Weder, 2013; Duran, Paula Lemes, & Seabra, 2012; Lin, Huang, & Dufresne, 2012).

17.3.1.1.1 Nanocellulose-Sulfoxide FunctionalizationWater has extensively used as a promising medium to stabilize the suspension of nano-cellulose with negatively charged surface groups, normally produced by hydrolysis of the cellulose with sulfuric acid, obtained in various polar liquid media (Berndt, Wesarg, Wiegand, Kralisch, & Müller, 2013; Jiang, Dallas, Ahn, & Hsieh, 2014). This has moti-vated some research work to produce stable nanocellulose with functionalized of dimethyl sulfoxide in N,N-dimethyl sulfoxide and N-methyl pyrrolidine, m-cresol, and formic acid (Chirayil, Mathew, & Thomas, 2014; Hua et al., 2014).

17.3.1.1.2 Nanocellulose-Amide FunctionalizationThe hydrophobic nanocellulose surface acquired by grafting of hexamethylene diiso-cyanate, following with reaction with amines. Furthermore, the amine-functionalized nanocellulose with positively charged, reported to be antimicrobial active in biomedi-cal applications (Anirudhan & Rejeena, 2014; Barazzouk & Daneault, 2011; Jebali et al., 2013). The surface functionalized nanocellulose presented antibacterial activity against both Gram-positive and negative bacteria, even at very low concentrations of antimi-crobial agent on the surface, killing more than 99% of E. coli and S. aureus as concen-tration of nitrogen element up to 0.14% (Barazzouk & Daneault, 2011; Jafary, Khajeh Mehrizi, Hekmatimoghaddam, & Jebali, 2015; Moritz et al., 2014).


17.3.1.1.3 Nanocellulose-Silane FunctionalizationThe silane functionalization usually improves the degree of cross-linking in the inter-face of nanocellulose as well as offering an excellent bonding (Mabrouk, Salon, Magnin, Belgacem, & Boufi, 2014). The silane surface functionalization undergoes hydrolysis, condensation, and bond formation stage of polysiloxane structures. In the presence of moisture, the hydroxylzable alkoxy group of silane derivatives results in the silanols for-mation. Moreover, the silanol reacts with the nanocellulose OH groups, forming stable covalent bonds to the cell wall that are chemisorbed onto the nanocellulose surface (Habibi, 2014; Kettunen et al., 2011).

Utilization of silane derivatives, including isopropyl dimethylchlorosilane, 3-amino-propyltriethoxysilane, and 3-glycidoxypropyltrimethoxysilane for surface silylation of nanocellulose resulting from the homogenization of its parenchymal cell walls (Jin et al., 2011). In other studies, nanocellulose has partially silylated by a series of alkyl-dimethylchlorosilanes, with the carbon backbone of the alkyl moieties ranging from a short-carbon length of isopropyl to longer length represented by n-butyl, n-octyl, and n-dodecyl. Infra-red analysis proved that chemical links formed with all sur-faces functionalized compounds, with aminopropyltriethoxysilane claimed the stron-gest link (Chun, Lee, Jeong, & Kim, 2012; Lee, Yoon, Lee, Lim, & Kim, 2014; Amin TermehYousefi et al., 2014). The morphological images of silane-nanocellulose shown that microfibrils morphology retained under mild silylation conditions and could be dispersed in a nonflocculating manner into organic solvents (Surip, Wan Jaafar, Azmi, & Anwar, 2012). It demonstrated as well that with a degree of substitution between 0.6 and 1.0, the silylated nanocellulose became readily dispersible in solvents of low polar-ity resulting in stable suspensions with birefringent behavior. However, at high silyat-ion degree of substitution greater than 1, the chains in the core of the crystals became silylated, resulting in the disintegration of the crystal and subsequently the loss of origi-nal morphology (Khan, Dussault, Salmieri, Safrany, & Lacroix, 2012). The hydro carbon chains provided by the application of silane restrain the swelling of nanocellulose by creating a cross-linked network. Therefore, the surface functionalization changed the character of nanocellulose from hydrophilic to hydrophobic while the crystalline structure of nanocellulose remained intact. Indeed, the silylation process by using of chlorodimethyl isopropylsilane commonly employed to modify the surface for use as hydrophobic feature (Ben Mabrouk et al., 2011). The hydrophobicity of the silylated nanocellulose performs with the reduction in its surface energy and increase in surface roughness. Owing to the nature of nanocellulose, it is commonly known that the OH group was facile to adsorption water and it consequently decreased the performance of nanocellulose if it was fabricated for any application. Therefore, hydrophobized nano-cellulose via partial surface silylation utilizing the same silylation agent mentioned that, too harsh process resulted in partially solubilization of nanocellulose and loss of nano-structure could occur (Dai, Fan, & Collins, 2013).

17.3.1.1.4 Nanocellulose-Acetyl FunctionalizationThe acetylation of nanocellulose improves the transparency and reduced the hydro-scopicity, which in turn reducing its moisture absorption (Cunha, Zhou, Larsson, & Berglund, 2014; Isogai, 2013; Khalil et al., 2014). The acetylation also reported to improve the optical properties, thermal degradation resistance, dimension stability,


and environmental degradation of cellulosic fibers. The pretreatment of nanocellulose with acetic anhydride substitutes the polymer OH groups of the cell wall with acetyl groups (CH3CO-R), which consequently modifying the features of nanocellulose to become more hydrophobic (Khalil et al., 2014). The reaction is known to precede full esterification of all the three OH of anhydro-d-glucose when it carried out in homoge-neous phase. The OH groups that react are those of the minor constituents of the nano-cellulose and those of amorphous nanocellulose (Isogai, 2013; Klemm et al., 2006). This is because of the OH groups in crystalline region with close packing and strong interchain bonding. Homogeneous and heterogeneous acetylation of bacterial nanocel-lulose is possible by utilizing acetic anhydride in acetic acid (Cherian et al., 2010). For homogeneous acetylation, the partially acetylated molecules immediately partitioned into the acetylating medium once it adequately soluble. Meanwhile, in heterogeneous conditions, the nanocellulose acetate remained insoluble and surrounded the crys-talline core of unreacted nanocellulose chains (Julasak Juntaro, Pommet, Mantalaris, Shaffer, & Bismarck, 2007). This consequently induced an occurrence of nanocellulose hydrolysis and acetylation of OH groups. The Fischer esterification of OH groups con-currently with the hydrolysis of amorphous nanocellulose domains has introduced as a viable one-pot reaction methodology that allows isolation of acetylation nanocellulose in one step process (Heßler & Klemm, 2009).

The acetyl substitution degree had a critical effect on the final acetylated nanocel-lulose. However, beyond the optimum degree of substitution and excessive acetylation decreased the original features of nanocellulose (Rehman et al., 2014). In many cases, nanocellulose partly acetylated to modify its physical properties while preserving the microfibrillar morphology.

17.3.1.1.5 Nanocellulose-Carboxylic FunctionalizationNanocellulose-carboxylic functionalization represents a broadly utilized water soluble nanocellulose derivative, applied where thickening, binding, suspending, stabilizing, and film forming features are important (Anirudhan & Rejeena, 2012; Holt, Stoyanov, Pelan, & Paunov, 2010; Parikka et al., 2012). Hydroxylmethyl groups of nanocellulose present on its structure can convert to the carboxylic form by using (2,2,6,6-tetrameth-ylpiperidine-1-oxyl) as an oxidation agent (Anirudhan & Rejeena, 2012). This oxida-tion reaction, which extremely discriminative of primary OH, is also simple and green to implement. It includes the application of 2,2,6,6-tetramethylpiperidine-1-oxyl as a stable nitroxyl radical, in the presence of NaOCl and NaBr (Wang et al., 2011). This carboxylic functionalization of nanocellulose includes a topologically confined reac-tion sequence, and because of the 2-fold screw axis of the nanocellulose chain, only half of the hydroxymethyl accessible groups available to react, while the other half bur-ied within the crystalline particles (Figure 17.6) (Mishra, Thirree, Manent, Chabot, & Daneault, 2010). This then creates a repulsive force between individual nanocellulose and prevents agglomeration. The resulted carboxylated nanocellulose maintained its primary morphological integrity and formed a homogeneous suspension once dispersed in water. It observed the effect of different nanocellulose loadings gave significant effect on the mechanical, thermal, sorption, and barrier properties of functionalized nanocel-lulose (Johnson, Zink-Sharp, & Glasser, 2011; Mishra, Manent, Chabot, & Daneault, 2011). The basis for these latter observations was the existence of the newly connected


carboxyl groups that instructed negative charges at the nanocellulose surface and con-sequently prompted electrostatic stabilization. Meanwhile, there are some reports on effect of pretreatments by suing the NaOH solution and dimethyl sulfoxide solvent on morphology, porous structure and macro/micro structures of carboxylated nanocellu-lose (Fujisawa, Okita, Fukuzumi, Saito, & Isogai, 2011). It found that the pretreatment gave uniform size of carboxylated nanocellulose (5–20 nm).

However, some reports on nanocellulose-carboxylic functionalization revealed that, though this medium presents a number of peculiarities that need for high excess of reagents and a long reaction time, it is possible to prepare the functionalized nanocel-lulose in the presence of solid NaOH particles (Benkaddour, Jradi, Robert, & Daneault, 2013). Regarding the mole fractions of the different repeating units, the functionalized sample, which prepared by using aqueous NaOH possess a static content. Nanocellulose exhibits an unconventional distribution of ether groups and unconventional features,

CH2OH

C4C5

O5

C2

OH

C1 O

nC3HO

TEMPO NaBr, NaCIO

EDC, NHS

OC PEG

O

nC1

OH

C3C2

O5C5C4

HO

NH

PEG-NH2

COOH

C4C5 O5

C1n

OC2C3HO

OH

Figure 17.6 Functionalized colloidal nanocellulose with TEMPO (Holt et al., 2010).


which means, nanocellulose displayed a preferred substitution at position O-6, and a block-like distribution of carboxymethyl groups along the nanocellulose backbones (Barazzouk & Daneault, 2012; Lin, Bruzzese, & Dufresne, 2012). These molecular and supermolecular properties lead to some new macroscopic features with different rheo-logical and colloidal behavior.

17.3.1.1.6 Nanocellulose-Aldehyde FunctionalizationOne of promising surface functionalization of nanocellulose is to introduce the reac-tive aldehyde functionalities with aqueous periodate oxidation (Chinga-Carrasco & Syverud, 2014; Jaušovec, Vogrinčič, & Kokol, 2015; Zhang et al., 2014). The aldehyde groups of functionalized nanocellulose easily and selectively converted further into various functional groups including carboxylic acids, sulfonates, and imines (Carlsson, Lindh, Nyholm, Strømme, & Mihranyan, 2014). Indeed, acetic anhydride added to the nanocellulose suspension in toluene after the solvent exchange process for having the hydrophobic features (Lu, Li, Chen, & Yu, 2014). This functionalized nanocellu-lose shown good flocculation performance for the wastewater treatment applications. Therefore, some studies used this type of modified nanocellulose to remove heavy metal from aqueous solution with promising results (Li & Xu, 2014; Sirviö et al., 2014).

17.3.1.1.7 Nanocellulose-Hyroxyapatite FunctionalizationThe adsorption ability of nanocellulose toward metal ions including Ni, Cd, PO43−, and NO3− increased via its functionalization with carbonated hydroxyapatite (Klemm et al., 2009; Zimmermann, LeBlanc, Sheets, Fox, & Gatenholm, 2011). Carbonated hydroxy-apatite has a composition and structure analogous to the bone apatite and displays greater bioactivity than pure hydroxyapatite (Hokkanen et al., 2014). Because of high specific surface area and small size, carbonated hydroxyapatite nanostructures can effi-ciently interact with nanocellulose structures, leading to the improvement (Taokaew, Seetabhawang, Siripong, & Phisalaphong, 2013).

17.3.1.2 Macromolecular Functionalization

The funtionalization of nanocellulose with macromolecules has currently investigated as a new way to produce good barrier materials and as possible solution to retain the advantages of nanocellulose and its surrounding medium (Anirudhan & Rejeena, 2013). The macromolecules used normally defined as a material which could signifi-cantly decrease the surface tension of water when utilized in very low concentrations. The noncovalent surface functionalization of nanocellulose typically made via adsorp-tion of the macromolecules (Lin & Dufresne, 2014; Nyström et al., 2010; Termehyousefi et al., 2015). The obtained macromolecules functionalized nanocellulose dispersed very well in nonpolar solvent (Bodin et al., 2007).

17.3.1.2.1 Nanocellulose-Epoxy FunctionalizationThe epoxy functionality introduced into the nanocellulose surface by grafting with gly-cidyl methacrylate followed by oxidation with cerium (IV) (Masoodi, El-Hajjar, Pillai, & Sabo, 2012). The reactive epoxy groups act as a starting point for further function-alization of the nanocellulose surface with ligands which usually do not react with the OH which present in native nanocellulose surface (Gabr et al., 2014; Lu, Askeland, & Drzal, 2008; Qamhia, Sabo, & Elhajjar, 2013). A main benefit of this method is that


the reaction conducted in aqueous media, thereby avoiding the use of organic solvents and laborious solvent exchange procedures (Ansari, Galland, Johansson, Plummer, & Berglund, 2014). By this technique, nanocellulose with a surface layer of moderate hydrophobicity prepared.

17.3.1.2.2 Nanocellulose-Cellulose Derivatives FunctionalizationThe cellulose derivatives have used to functionalize the surface properties of nanocel-lulose, because of their natural affinity toward nanocellulose (Liu, Choi, Gatenholm, & Esker, 2011; Siró & Plackett, 2010). Different approaches utilizing carboxymetyl cel-lulose for the surface functionalization of nanocellulose have reported, but the negative charge of carboxymethyl cellulose is disruptive for a high adsorption of nanocellulose. By contrast, unmodified hemicellulose derivatives including xyloglucans, arabinox-ylans, and O-acetyl galactoglucomannan can functionalized the surface of nanocel-lulose in considerable amount, and henceforth became promising starting materials for its functionalization (Kramer et al., 2006; Liu & Berglund, 2013; Ramimoghadam, Bagheri, & Abd Hamid, 2014). In order to use hemicellulose derivatives as a function-alize agents for surface modification of nanocellulose, the main chain of hemicellulose derivatives should preserve its native structure in respect to molar mass, composition, and degree of substitution (Pahimanolis et al., 2013). This is necessary to reveal high affinity of hemicellulose derivatives toward nanocellulose.

17.3.1.2.3 Nanocellulose-Polymer FunctionalizationMostly, physical properties of nanocellulose are changed by derivation, which involves chemical functionalization of nanocellulose structure (Taokaew et al., 2013). A good balance of features obtained if the crystallinity of nanocellulose in the polymer net-work reduced and/or the compatibility with a base polymer improved. The emphasize given to the study of changes in crystallinity and molecular structure of nanocellulose when it was under a combination of nonhazardous and environmentally begin poly-mer system (Anirudhan & Rejeena, 2013; Lin & Dufresne, 2014; Nyström et al., 2010). Besides, the main objectives of polymer-functionalized nanocellulose were to explore such polymer system to give additional functionality of nanocellulose for better disper-sion and solubility (Bodin et al., 2007; Gholamrezaei, Salavati-Niasari, Bazarganipour, Panahi-Kalamuei, & Bagheri, 2014). Lately, specific interest has grown in researching the soluble level of functionalized nanocellulose, there have been a lot of efforts to fully understand and control the solution mechanism.

17.3.1.2.3.1 Nanocellulose-Polysulfone Functionalization. The polysulfone is a type of high-performance polymer with outstanding thermal and chemical stability, flex-ibility, and strength, as well as a good film forming properties and high glass transition temperature. In spite of the substantial improvement on its applications, the polysul-fone has some restrictions such as stress cracking, intrinsic hydrophilicity, and weath-ering features (Bai, Zhou, & Zhang, 2015; Ferraz & Mihranyan, 2014). Therefore, the contribution of hydrophilicity functionalization to improve the hydrophilicity and anti-fouling properties of polysulfone membrane material is essentially required (Chekin, Raoof, Bagheri, & Hamid, 2012; Gao, Li, Zhong, Zhang, & Ding, 2014). Therefore, some research works have brought the functional nanocellulose into polysulfone net-works not only to overcome these restrictions, but more important, widen the potential


application areas of polysulfone materials (Bai, Wang, Sun, & Zhang, 2015; Grygiel et al., 2014). It is believed that the hydrophobization chain segment of amphilic nano-cellulose provided compatibility between its polymer chains and polysulfone, while hydrophilic and anti-fouling protection were then created from the surface OH of amphilic nanocellulose (Gao et al., 2014). The flux of blend membranes revealed that the surface enrichment of amphilic nanocellulose expressively improves the hydrophi-licity of the surface and polysulfone antipollution ability.

17.3.1.2.3.2 Nanocellulose-Polypropylene Functionalization. The grafting onto the approach to graft maleated polypropylene onto the surface of tunicate-extracted nanocellulose has resulted on grafted nanocellulose displayed very good compatibility and high adhesion when dispersed in atactic polypropylene (Lunz, Cordeiro, Mota, & Marques, 2012; Savadekar & Mhaske, 2012; Xie, Gao, & Zhao, 2010).

17.3.1.2.3.3 Nanocellulose-Polylactic Acid Functionalization. The surface func-tionalization of nanocellulose with polylactic acid is done via a ring-opening polym-erization approach. Polylactic functionalized nanocellulose displayed a stable colloidal behavior in organic solvents in comparison with native nanocellulose that formed aggregates and sediment over time. In addition, as shown from a polarized light micro-scope, the dispersion of polylactic functionalized nanocellulose was more homoge-neous prior to solvent evaporation (Aulin, Karabulut, Tran, Wågberg, & Lindström, 2013; Baheti, Mishra, Militky, & Behera, 2014). The thermal measurement suggested a better interaction between functionalized nanocellulose and the nonpolar matrix, whereby the functionalized nanocellulose function as a nucleating agent which in turn could increase its crystallinity (Jonoobi, Harun, Mathew, & Oksman, 2010; Jonoobi, Mathew, Abdi, Makinejad, & Oksman, 2012). Recent studies of polylactic functional-ized nanocellulose prove also the positive impact of nanocellulose on water vapor bar-rier properties. However, the polylatic functionalized nanocellulose did not display a transparent appearance, which might be a result from pore formation (DY Liu, Yuan, Bhattacharyya, & Easteal, 2010). It reported that, increase amount of pore related to the increase in number of nanocellulose concentrations (Aulin et al., 2013).

17.3.1.2.3.4 Nanocellulose-Polyurethane Functionalization. The polyurethane is broadly utilized in many applications, which prepared from isocyanate and polyol. In a commercial sense, polyol utilized for developed polyurethane predominantly derived from petroleum-based resources (Auad, Contos, Nutt, Aranguren, & Marcovich, 2008; Bagheri, Muhd Julkapli, & Bee Abd Hamid, 2014; Pei, Malho, Ruokolainen, Zhou, & Berglund, 2011; Wu, Henriksson, Liu, & Berglund, 2007). With the raising problem with fossil energy resource depletion and also environmental footprint, there is a robust worldwide interest to explore renewable bioresources as an alternative feedstock for making the polyurethane. Taking into consideration those stated previously, nanocel-lulose prepared with phosphoric acid and entirely utilized to modify polyurethane (Pei et al., 2011). Role of nanocellulose as a reinforcement material and oligosaccharides from the hydrolyzed cellulose partly replaced polyol (Aranguren, Marcovich, Salgueiro, & Somoza, 2013).

The functionalization process starts with the fabrication of nanocellulose in an anhy-drous phosphoric acid system with medical absorbent cotton as its raw material. After


ammonia neutralization, the whole system with produced phosphates and hydrolyzed saccharides utilized as a modifier for preparing polyurethane foam (Auad et al., 2012; Juntaro, Ummartyotin, Sain, & Manuspiya, 2012). Adding the modifier meaningfully enhanced mechanical properties and flame retardancy of nanocellulose-functionalized polyurethane without an inferior thermal conductivity. The X-ray and micrograph analysis confirmed that the nanocellulose react well with polyurethane with a diameter of 10 nm and had more uniform cells and regular skeleton structure as compared with neat polyurethane (Floros et al., 2012; Liu, Song, Shang, Song, & Wang, 2012).

17.3.1.2.3.5 Nanocellulose-Chitosan Functionalization. Chitosan is traditionally used in water purification, it is mostly effective toward negatively charged acidic dyes due to functional group present (NH2+) (Azeredo et al., 2010). However, the water permeability and water stability of chitosan in different pH conditions, especially after cross linking will be of advantage in fabricating water cleaning membranes (Bagheri, KG, & Hamid, 2013; Khan et al., 2012; Tomé et al., 2013). The biggest advantage with the process was the fabrication of a loose and nonaggregated network, which is expected to provide easy availability of surface groups on nanocellulose as adsorption sites for con-taminates (Dehnad, Emam-Djomeh, Mirzaei, Jafari, & Dadashi, 2014). High concen-tration of nanocellulose as a functional entity is used with an aim to have high process efficiency (Pereda, Dufresne, Aranguren, & Marcovich, 2014).

17.3.2 Nanocellulose: Inorganic Compounds Functionalization

Functionalization of inorganic compounds toward nanocellulose structure is strongly considered by the grafting of metal/metal oxides particles at its OH positions. This functionalization process strongly induced the surface functionality of nanocellulose if it was fabricated as a composite structure. In recent years, researches have strongly attempted to functionalized metal/metal oxide at the OH position of nanocellulose for dielectric and piezoelectric responses, which was considered to result in the electrome-chanical characteristic of nanocellulose. Structural characterization of inorganic func-tionalized nanocellulose mainly carried out by their solids by well-developed solid-state technique such as FT-IR, XPS, EDX, and solid state C NMR.

17.3.2.1 Nanocellulose-Titanium Oxide Functionalization

The nanocellulose-functionalized TiO2 is strongly enhanced the photocatalytic anti-microbial effect of TiO2. It has proved that better to use functionalized nanocellulose either alone or for functionalization with TiO2 if anti-bacterial properties are desired (Bardet, Belgacem, & Bras, 2013; Wesarg et al., 2012). The chemical surface function-alization applied on nanocellulose did not negatively influence this valuable property of nanocellulose but help for monitoring this property, which could be very useful for paper, packaging, and composites (Miettunen et al., 2014).

17.3.2.2 Nanocellulose-Fluorine Functionalization

In general, the hydrophobicity of nanocellulose attained by lowering the surface free energy (Chun et al., 2012; Pandey et al., 2014). For this purpose, surface functionalization


of nanocellulose with fluorine is the most effective approach to lower the surface free energy because of its small atomic radius and the biggest electronegativity among atoms (Bagheri, Julkapli, & Hamid, 2014; Korhonen, Hiekkataipale, et al., 2011). Once the fluorine replaced by other elements of nanocellulose including C and H, the surface free energy reduces in the order of CH2>CH3>CF>CF2H>CF3, which the CF3 groups on the surface gives the lowest surface free energy of the functionalized nanocellulose (Chiappone et al., 2014; Miettunen et al., 2014; Pandey et al., 2014).

17.3.2.3 Nanocellulose-Gold Functionalization

Nanocellulose-functionalized gold (Au) nanoparticles assist as an outstanding sup-port for enzyme immobilization, including cyclodextrin glycosyl transferase and alco-hol oxidase, which immobilized on nanocellulose with high enzyme loading capacity (Lokanathan et al., 2013; Park, Chang, Jeong, & Hyun, 2013; Shi, Phillips, & Yang, 2013). The improvement on enzyme loading because of the greater exposed specific surface area provided by the nanocellulose-Au nanopartilces. It reported that Au nanoparticles with the size range 2–7 nm able to be deposited on nanocellulose by the reduction of AuCl3·3H2O with NaBH4, which resulted on covalent binding of thiotic acid to the nanocellulose-functionalized Au (Bodin et al., 2007; Stevanic et al., 2011).

17.3.2.4 Nanocellulose-Silver Functionalization

Nanocellulose with functionalization of silver (Ag) uses in wound dressing application to mitigate the bacterial growth in areas of high humidity produced (Bagheri, Chekin, & Hamid, 2014; Berndt et al., 2013; Díez et al., 2011). The synthesize of nanocellulose-functionalized Ag started from reduction of AgNO3 with NaBH4 to cellulose nano-fibrils (Dong, Snyder, Tran, & Leadore, 2013). The nanocellulose fibrils excreted by bacteria including Gluconacterobacter xylinum are 200 times finer than cotton fiber. This in turn result extraordinarily high surface area because of their high aspect ratio (Figure 17.7) (Suman, Kardam, Gera, & Jain, 2015). The nanocellulose-functionalized Ag also demonstrated antimicrobial performance of more than 99.99% against E. coli and S. aureus (Barud et al., 2011)8tt#[.

17.3.2.5 Nanocellulose-Pd Functionalization

Functionalization of nanocellulose with palladium (Pd) nanoparticles with average size of 3.6 ± 0.8 nm have synthesized by reduction of PdCl2 with H2 in the presence of

Silver

CNC

100 nm

Figure 17.7 Micrograph of nanocellulose-functionalized silver nanoparticles.


nanocellulose (Lemahieu, Bras, Tiquet, Augier, & Dufresne, 2011; Zhou et al., 2012). Nanocellulose serves as support matrix for the formation of stable Pd nanoparticles, and providing the necessary sites for substrate to adsorb and participate in further chemical reaction (Zander, Dong, Steele, & Grant, 2014). The fast rate of reaction in comparison to other Pd-functionalized materials could be attributed to both smaller Pd nanoparticles size and the positively charge on the surface of nanocellulose (Rezayat, Blundell, Camp, Walsh, & Thielemans, 2014).

17.3.2.6 Nanocellulose-CdS Functionalization

As a semiconductor material, cadmium sulfide (CdS) has find application in solar cells, optoelectronic, and electronic devices (Bagheri, Chandrappa, & Hamid, 2013; Rajawat, Kardam, Srivastava, & Satsangee, 2013). Furthermore, functionalized of nanocellulose with CdS using electroless deposition technique become an universal platform for pro-ducing nanosclae functional material with advantages over protein or DNA templating in terms of costs, versatility, and simplicity (Fazilova, Yugai, & Rashidova, 2011). The morphology-controlled CdS nanocrystals with nanocellulose, which have prepared by a hydrothermal method, to act as high efficiency photocatalysis (Rajawat et al., 2013).

17.4 Applications of Functionalized Nanocellulose

On the basis of its unique properties, functionalized nanocellulose has envisioned rang-ing from bulk applications including rheological modifier, composite reinforcement, or paper additive, to high-end applications such as tissue engineering, drug delivery, and functional materials.

17.4.1 Wastewater Treatment

The wastewater produced from different kinds of industries normally contains very fine suspended solids, dissolved solids, inorganic and organic particles, metals, and other impurities. Due to very small size of the particles and the presence of surface charge, the task to bring these particles closer to the heavier mass for settling and filtration becomes challenging (Dimic-Misic et al., 2013; Fazilova et al., 2011; Suopajärvi, Liimatainen, Karjalainen, Upola, & Niinimäki, 2015). Functionalized nanocellulose has employed for the removal of organic/inorganic pollutants from industrial effluents via the chemi-cal precipitation, membrane separation, ion exchange, flocculation, electrolysis, and evaporation. Native nanocellulose has packed aggregates and high fractal dimension, whereas functionalized nanocellulose has lower fractal dimension results from large, highly branched, and loosely bound structures. Besides, few functional groups in func-tionalized nanocellulose are able to capture the metal ions through some derivatization. Some of these techniques based on utilizing amine and carboxylate groups as chelat-ing agents and/or catalytic and selective oxidation of primary OH groups of nanocel-lulose (Zhen, 2011). The succinylation reaction has also exposed to be an alternative in cellulose functionalization. Therefore, the functionalized nanocellulose has recently utilized in the coagulation–flocculation treatment of wastewater. The combined


coagulation–flocculation treatment of municipal wastewater led to a lower residual turbidity and COD in a settled suspension, with significantly decreased total chemi-cal consumption (Kardam, Raj, Srivastava, & Srivastava, 2014; Suopajärvi, Koivuranta, Liimatainen, & Niinimäki, 2014; Suopajärvi, Liimatainen, Hormi, & Niinimäki, 2013).

For example, the dicarboxylic acid-nanocellulose showed reduction in turbidity and COD removal performance of wastewater than those of commercial reference polymer in low dosage, with considerably decreased chemical consumption relative to coagula-tion (Mishra et al., 2010; Suopajärvi et al., 2013). The results showed that the dicar-boxylic nanocellulose able to flocculate wastewater very proficiently. The wastewater flocs produced with functionalized nanocellulose were smaller and rounder than those produced with the commercial reference polymer with the flocs produced with anionic nanocellulose were more stable under shear than the flocs produced with the reference polymer (Fujisawa et al., 2011; Lin, Bruzzese, et al., 2012). This in turn makes dicarbox-ylic nanocellulose has good performance within the chosen pH range and high stability in aqueous suspensions over a long period of time.

17.4.2 Biomedical Applications

Nanocellulose-functionalized Ag with antimicrobial properties has been found to inhibit the growth of both E. coli and S. aureus. The greater effectiveness of the nanocellulose-functionalized Ag solution suggests a favorable interaction between nanocellulose and the bacteria growth inhibition (Berndt et al., 2013). The smaller nanocellulose particle sizes predispose in Ag nanoparticles suspension use in antiseptic solution or in wound healing gels at greater nanocellulose concentration. Isolating a solid material by freeze drying allows it to be utilized for the manufacture of biodegradable wound dressing (Díez et al., 2011; Dong et al., 2013).

The functionalized nanocellulose has applied also as an agent for enzyme or protein immobilization because of its large surface area and porous structure (Barud et al., 2011; Suman et al., 2015)>. For example, nanocellulose-functionalized peroxidase through activation with cyanogen bromide has been used for the removal of chlori-nated phenolic compounds in aqueous medium. The immobilized peroxidase demon-strates improved removal of chlorinated phenolic compounds compared to its soluble counterpart. This probably is because of protective effects of the immobilization toward enzyme deactivation, as well as product precipitation induced by the conjugate amino groups.

17.4.3 Biosensor and Bioimaging

The functional groups on the surface of nanocellulose could be conjugated with dif-ferent biological moieties or serve as binding sites for inorganic nanoparticles, which enable its utilize in biosensing or bioimaging. One class of biomolecules conjugated to functionalized nanocellulose is nucleic acids using TEMPO-mediated oxidation and an amino modifier. This allows hybridizing reversibly using the molecular recogni-tion ability of the nucleic acid to form a duplex that decoupled at greater tempera-ture (Amiri, Salavati-Niasari, Farangi, Mazaheri, & Bagheri, 2015; Carlsson et al., 2014; Jaušovec et al., 2015).


Another efficient method for attaching nanocellulose to nucleic acids is through the functionalization of bifunctional oxirane 1,4-butane-diol diglycidyl ether. This functionalization product used to purify complementary nucleic acids compounds by affinity chromatography. This method could probably as well be adapted for use with functionalized nanocellulose to developed chromatographic materials with high surface area for a variety of applications (Zhang et al., 2014). Meanwhile, nanocellu-lose functionalized chitosan with the competitive binding assays using triclosan and dodecylsulfate anions demonstrate the great sensitivity and potential use in the surfac-tant detection.

Furthermore, functionalization of inorganic material with nanocellulose can be used as labels for electrical detection of nucleic acid hybridization. For example, Au-carboxylated nanocellulose utilized as labeled nucleic acids probes to identify the complementary target of nucleic acid sequence (Edwards et al., 2013). The carboxyl and hydroxyl groups of carboxylated nanocellulose trigger a coordination effect to adsorb metallic cations and alloy nanoparticles, preventing the agglomeration of nanoparticles. Meanwhile, nanocellulose-functionalized TiO2 with promising conducting pathways for electron in a relatively open nanocellulose structure suitable for the methemoglobin immobilization.

17.4.4 Catalysis

The uses of functionalized nanocellulose as a support matrix for new heterogeneous catalysis are growing. The advantage of highly dispersed inorganic nanoparticles ensures efficient contact among substrates and the inorganic material surface for reactions to occur. The catalytic properties of nanocellulose-functionalized Pd have exploited for the hydrogenation of phenol to cyclohexanone and the Heck coupling reaction of sty-rene with iodobenzene. It recorded that up to 90% conversion of phenol to cyclohexa-none achieved after 24 h at room temperature using H2 with a 7:1 substrate to catalyst ratio (Zhou et al., 2012).

17.5 Conclusion

Cellulose is the most plentiful, renewable biopolymer resource. Nanocellulose shows various areas of possible application owing to its biocompatibility, biodegradability, and nontoxicity properties. One of the challenges for some applications of nanocel-lulose is its hydrophilicity, which has dispersion, barrier, and permeability limitations. Therefore, surface functionalization of nanocellulose with organic and inorganic mole-cules/macromolecules is often necessary. The functionalization of nanocellulose can be achieved by targeting the OH groups at the nanocellulose surface in chemical reaction including silylation for hybrophobization of nanocellulose, esterification to introduce group with antimicrobial activities and initiator groups for controlled radical polym-erizations. The functionalized nanocellulose provides effective, stable, and regenerable nanomaterials for various applications including wastewater treatment, hydrogen stor-age, adsorbent, reinforcement agents, and others. This review focuses on functionalized nanocrystalline cellulose and its applications in different areas.


Acknowledgment

This work is financially supported by University Malaya Research Grant (UMRG RP022-2012E) and Fundamental Research Grant Scheme (FRGS: FP049-2013B) by Universiti Malaya and Ministry of High Education, Malaysia, respectively.

References

Abitbol, T., Johnstone, T., Quinn, T. M., & Gray, D. G. Reinforcement with cellulose nanocrystals of poly (vinyl alcohol) hydrogels prepared by cyclic freezing and thawing. Soft Matter, 7(6), 2373–2379, 2011.

Ahola, S., Österberg, M., & Laine, J. Cellulose nanofibrils—adsorption with poly (amideamine) epichlorohydrin studied by QCM-D and application as a paper strength additive. Cellulose, 15(2), 303–314, 2008.

Amiri, O., Salavati-Niasari, M., Farangi, M., Mazaheri, M., & Bagheri, S. Stable Plasmonic-Improved dye Sensitized Solar Cells by Silver Nanoparticles Between Titanium Dioxide Layers. Electrochim. Acta, 152, 101–107, 2015.

Anirudhan, T., & Rejeena, S. Adsorption and hydrolytic activity of trypsin on a carboxylate-functionalized cation exchanger prepared from nanocellulose. J. Colloid Interf. Sci., 381(1), 125–136, 2012.

Anirudhan, T. S., & Rejeena, S. R. Selective adsorption of hemoglobin using polymer-grafted-magnetite nanocellulose composite. Carbohydr. Polym, 93(2), 518–527, 2013.

Anirudhan, T. S., & Rejeena, S. R. Poly (acrylic acid-co-acrylamide--co-2-acrylamido-2-methyl-1-propanesulfonic acid)-grafted nanocellulose/poly (vinyl alcohol) composite for the in vitro gastrointestinal release of amoxicillin. J Appl. Polym. Sci., 131(17), 2014.

Ansari, F., Galland, S., Johansson, M., Plummer, C. J., & Berglund, L. A. Cellulose nanofiber network for moisture stable, strong and ductile biocomposites and increased epoxy curing rate. Compos. A: Appl. Sci. Manufactur., 63, 35–44, 2014.

Aranguren, M. I., Marcovich, N. E., Salgueiro, W., & Somoza, A. Effect of the nano-cellulose content on the properties of reinforced polyurethanes. A study using mechanical tests and positron anihilation spectroscopy. Polym. Test., 32(1), 115–122, 2013.

Auad, M. L., Contos, V. S., Nutt, S., Aranguren, M. I., & Marcovich, N. E. Characterization of nanocellulose-reinforced shape memory polyurethanes. Polym. Int., 57(4), 651–659, 2008.

Auad, M. L., Richardson, T., Hicks, M., Mosiewicki, M. A., Aranguren, M. I., & Marcovich, N. E. Shape memory segmented polyurethanes: Dependence of behavior on nanocellulose addi-tion and testing conditions. Polym. Int., 61(2), 321–327, 2012.

Aulin, C., Karabulut, E., Tran, A., Wågberg, L., & Lindström, T. Transparent nanocellulosic mul-tilayer thin films on polylactic acid with tunable gas barrier properties. ACS Appl. Mater. Interf., 5(15), 7352–7359, 2013.

Aulin, C., Salazar-Alvarez, G., & Lindström, T. High strength, flexible and transparent nanofi-brillated cellulose–nanoclay biohybrid films with tunable oxygen and water vapor perme-ability. Nanoscale, 4(20), 6622–6628, 2012.

Azeredo, H., Mattoso, L. H. C., Avena-Bustillos, R. J., Munford, M. L., Wood, D., & McHugh, T. H. Nanocellulose reinforced chitosan composite films as affected by nanofiller loading and plas-ticizer content. J. Food Sci., 75(1), N1–N7, 2010.

Bagheri, S., Chandrappa, K., & Hamid, S. B. A. Generation of Hematite nanoparticles via Sol-gel method. Research J. Chem. Sci. ISSN, 2231, 606X, 2013.


Bagheri, S., Chekin, F., & Hamid, S. B. A. Cobalt doped titanium dioxide nanoparticles: Synthesis, characterization and electrocatalytic study. J. Chin. Chem. Soc., 61(6), 702–706, 2014.

Bagheri, S., Julkapli, N. M., & Hamid, S. B. A. Functionalized activated carbon derived from biomass for photocatalysis applications perspective. Int. J. Photoenergy, 2014.

Bagheri, S., KG, C., & Hamid, S. B. A. Facile synthesis of nano-sized ZnO by direct precipitation method. Der Pharma Chem., 5(3), 265–270, 2013.

Bagheri, S., Muhd Julkapli, N., & Bee Abd Hamid, S. Titanium dioxide as a catalyst support in heterogeneous catalysis. Scientific World J., 2014.

Baheti, V., Mishra, R., Militky, J., & Behera, B. Influence of noncellulosic contents on nano scale refinement of waste jute fibers for reinforcement in polylactic acid films. Fibers Polym., 15(7), 1500–1506, 2014.

Bai, H., Wang, X., Sun, H., & Zhang, L. Permeability and morphology study of polysulfone com-posite membrane blended with nanocrystalline cellulose. Desalination and Water Treatment, 53(11), 2882–2896, 2015.

Bai, H., Zhou, Y., & Zhang, L. Morphology and Mechanical properties of a new nanocrystalline cellulose/polysulfone composite membrane. Adv. Polym. Technol., 34(1), 2015.

Bai, W., Holbery, J., & Li, K. A technique for production of nanocrystalline cellulose with a nar-row size distribution. Cellulose, 16(3), 455–465, 2009.

Barazzouk, S., & Daneault, C. Spectroscopic characterization of oxidized nanocellulose grafted with fluorescent amino acids. Cellulose, 18(3), 643–653, 2011.

Barazzouk, S., & Daneault, C. Tryptophan-based peptides grafted onto oxidized nanocellulose. Cellulose, 19(2), 481–493, 2012.

Bardet, R., Belgacem, M. N., & Bras, J. Different strategies for obtaining high opacity films of MFC with TiO2 pigments. Cellulose, 20(6), 3025–3037, 2013.

Barud, H. S., Regiani, T., Marques, R. F., Lustri, W. R., Messaddeq, Y., & Ribeiro, S. J. Antimicrobial bacterial cellulose-silver nanoparticles composite membranes. J. Nanomater., 2011, 10, 2011.

Beck, S., Bouchard, J., & Berry, R. Controlling the reflection wavelength of iridescent solid films of nanocrystalline cellulose. Biomacromolecules, 12(1), 167–172, 2010.

Beck, S., Bouchard, J., & Berry, R. Dispersibility in water of dried nanocrystalline cellulose. Biomacromolecules, 13(5), 1486–494, 2012.

Ben Mabrouk, A., Kaddami, H., Magnin, A., Belgacem, M. N., Dufresne, A., & Boufi, S. Preparation of nanocomposite dispersions based on cellulose whiskers and acrylic copoly-mer by miniemulsion polymerization: Effect of the silane content. Polym. Eng. Sci., 51(1), 62–70, 2011.

Benkaddour, A., Jradi, K., Robert, S., & Daneault, C. Grafting of polycaprolactone on oxidized nanocelluloses by click chemistry. Nanomaterials, 3(1), 141–157, 2013.

Berndt, S., Wesarg, F., Wiegand, C., Kralisch, D., & Müller, F. A. Antimicrobial porous hybrids consisting of bacterial nanocellulose and silver nanoparticles. Cellulose, 20(2), 771–783, 2013.

Biyani, M. V., Foster, E. J., & Weder, C. Light-healable supramolecular nanocomposites based on modified cellulose nanocrystals. ACS Macro Lett., 2(3), 236–240, 2013.

Bodin, A., Ahrenstedt, L., Fink, H., Brumer, H., Risberg, B., & Gatenholm, P. Modification of nanocellulose with a xyloglucan–RGD conjugate enhances adhesion and proliferation of endothelial cells: Implications for tissue engineering. Biomacromolecules, 8(12), 3697–3704,. 2007.

Boluk, Y., Zhao, L., & Incani, V. Dispersions of nanocrystalline cellulose in aqueous polymer solutions: Structure formation of colloidal rods. Langmuir, 28(14), 6114–6123, 2012.

Bondeson, D., Mathew, A., & Oksman, K. Optimization of the isolation of nanocrystals from microcrystalline cellulose by acid hydrolysis. Cellulose, 13(2), 171–180, 2006.


Braun, B., & Dorgan, J. R. Single-step method for the isolation and surface functionalization of cellulosic nanowhiskers. Biomacromolecules, 10(2), 334–341, 2008.

Brinchi, L., Cotana, F., Fortunati, E., & Kenny, J. Production of nanocrystalline cellulose from lignocellulosic biomass: Technology and applications. Carbohydr. Polym., 94(1), 154–169, 2013.

Carlsson, D. O., Lindh, J., Nyholm, L., Strømme, M., & Mihranyan, A. Cooxidant-free TEMPO-mediated oxidation of highly crystalline nanocellulose in water. RSC Adv., 4(94), 52289–52298, 2014.

Cervin, N. T., Aulin, C., Larsson, P. T., & Wågberg, L. Ultra porous nanocellulose aerogels as separation medium for mixtures of oil/water liquids. Cellulose, 19(2), 401–410, 2012.

Chauhan, G. S., Mahajan, S., & Guleria, L. K. Polymers from renewable resources: Sorption of Cu 2+ ions by cellulose graft copolymers. Desalination, 130(1), 85–88, 2000.

Chekin, F., Raoof, J. B., Bagheri, S., & Hamid, S. B. A. Fabrication of chitosan-multiwall carbon nanotube nanocomposite containing ferri/ferrocyanide: Application for simultaneous detec-tion of D-penicillamine and tryptophan. J. Chin. Chem. Soc., 59(11), 1461–1467, 2012.

Cherian, B. M., Leão, A. L., de Souza, S. F., Thomas, S., Pothan, L. A., & Kottaisamy, M. Isolation of nanocellulose from pineapple leaf fibres by steam explosion. Carbohydr. Polym., 81(3), 720–725, 2010.

Chiappone, A., Bella, F., Nair, J. R., Meligrana, G., Bongiovanni, R., & Gerbaldi, C. Structure–Performance Correlation of Nanocellulose-Based Polymer Electrolytes for Efficient Quasi-solid DSSCs. ChemElectroChem, 1(8), 1350–1358, 2014.

Chinga-Carrasco, G., & Syverud, K. Pretreatment-dependent surface chemistry of wood nano-cellulose for pH-sensitive hydrogels. J. Biomater. Appl., 29(3), 423–432, 2014.

Chirayil, C. J., Mathew, L., & Thomas, S. Review of recent research in nano cellulose preparation from different lignocellulosic fibers. Rev. Adv. Mater. Sci, 37, 20–28, 2014.

Chun, S.-J., Lee, S.-Y., Jeong, G.-Y., & Kim, J. H. Fabrication of hydrophobic self-assembled monolayers (SAM) on the surface of ultra-strength nanocellulose films. J. Indust. Eng. Chem., 18(3), 1122–1127, 2012.

Cranston, E. D., & Gray, D. G. Morphological and optical characterization of polyelectrolyte multilayers incorporating nanocrystalline cellulose. Biomacromolecules, 7(9), 2522–2530, 2006.

Cranston, E. D., Gray, D. G., & Rutland, M. W. Direct surface force measurements of poly-electrolyte multilayer films containing nanocrystalline cellulose. Langmuir, 26(22), 17190–17197, 2010.

Cunha, A. G., Zhou, Q., Larsson, P. T., & Berglund, L. A. Topochemical acetylation of cellulose nanopaper structures for biocomposites: Mechanisms for reduced water vapour sorption. Cellulose, 21(4), 2773–2787, 2014.

Dai, D., Fan, M., & Collins, P. Fabrication of nanocelluloses from hemp fibers and their applica-tion for the reinforcement of hemp fibers. Ind. Crops Prod., 44, 192–199, 2013.

Dehnad, D., Emam-Djomeh, Z., Mirzaei, H., Jafari, S.-M., & Dadashi, S. Optimization of physi-cal and mechanical properties for chitosan–nanocellulose biocomposites. Carbohydr. Polym., 105, 222–228, 2014.

Díez, I., Eronen, P., Österberg, M., Linder, M. B., Ikkala, O., & Ras, R. H. Functionalization of nanofibrillated cellulose with silver nanoclusters: Fluorescence and antibacterial activity. Macromol. Biosci., 11(9), 1185–1191, 2011.

Dimic-Misic, K., Puisto, A., Gane, P., Nieminen, K., Alava, M., Paltakari, J., & Maloney, T. The role of MFC/NFC swelling in the rheological behavior and dewatering of high consistency furnishes. Cellulose, 20(6), 2847–2861, 2013.


Dong, H., Snyder, J. F., Tran, D. T., & Leadore, J. L. Hydrogel, aerogel and film of cellulose nano-fibrils functionalized with silver nanoparticles. Carbohydr. Polym., 95(2), 760–767, 2013.

Duran, N., Paula Lemes, A., & B Seabra, A. Review of cellulose nanocrystals patents: Preparation, composites and general applications. Recent Patents Nanotechnol., 6(1), 16–28, 2012.

Edwards, J. V., Prevost, N., French, A., Concha, M., DeLucca, A., & Wu, Q. Nanocellulose-based biosensors: Design, preparation, and activity of peptide-linked cotton cellulose nanocrystals having fluorimetric and colorimetric elastase detection sensitivity, 2013.

Elazzouzi-Hafraoui, S., Nishiyama, Y., Putaux, J.-L., Heux, L., Dubreuil, F., & Rochas, C. The shape and size distribution of crystalline nanoparticles prepared by acid hydrolysis of native cellulose. Biomacromolecules, 9(1), 57–65, 2007.

Fattori, V., Melucci, M., Ferrante, L., Zambianchi, M., Manet, I., Oberhauser, W., . . . Camaioni, N. Poly (lactic acid) as a transparent matrix for luminescent solar concentrators: A renew-able material for a renewable energy technology. Energy Environ. Sci., 4(8), 2849–2853, 2011.

Fazilova, S., Yugai, S., & Rashidova, S. S. Structural investigation of polysaccharides and nano-compositions based on them. Russ. J. Bioorg. Chem., 37(7), 786–790, 2011.

Feese, E., Sadeghifar, H., Gracz, H. S., Argyropoulos, D. S., & Ghiladi, R. A. Photobactericidal porphyrin-cellulose nanocrystals: Synthesis, characterization, and antimicrobial properties. Biomacromolecules, 12(10), 3528–3539, 2011.

Ferraz, N., & Mihranyan, A. Is there a future for electrochemically assisted hemodialysis? Focus on the application of polypyrrole-nanocellulose composites. Nanomedicine, 9(7), 1095–1110, 2014.

Filpponen, I., & Argyropoulos, D. S. Regular linking of cellulose nanocrystals via click chemis-try: Synthesis and formation of cellulose nanoplatelet gels. Biomacromolecules, 11(4), 1060–1066, 2010.

Filson, P. B., & Dawson-Andoh, B. E. Sono-chemical preparation of cellulose nanocrystals from lignocellulose derived materials. Bioresource Technol., 100(7), 2259–2264, 2009.

Floros, M., Hojabri, L., Abraham, E., Jose, J., Thomas, S., Pothan, L., . . . Narine, S. Enhancement of thermal stability, strength and extensibility of lipid-based polyurethanes with cellulose-based nanofibers. Polym. Degrad. Stab., 97(10), 1970–1978, 2012.

Fortunati, E., Peltzer, M., Armentano, I., Torre, L., Jiménez, A., & Kenny, J. Effects of modified cellulose nanocrystals on the barrier and migration properties of PLA nano-biocomposites. Carbohydr. Polym., 90(2), 948–956, 2012.

Fujisawa, S., Okita, Y., Fukuzumi, H., Saito, T., & Isogai, A. Preparation and characterization of TEMPO-oxidized cellulose nanofibril films with free carboxyl groups. Carbohydr. Polym., 84(1), 579–583, 2011.

Gabr, M. H., Phong, N. T., Okubo, K., Uzawa, K., Kimpara, I., & Fujii, T. Thermal and mechani-cal properties of electrospun nano-celullose reinforced epoxy nanocomposites. Polym. Test., 37, 51–58, 2014.

Gao, Y., Li, B., Zhong, L., Zhang, L., & Ding, Z. Effect of nano-amphiphilic cellulose as a modi-fier to PSf composite membranes. Vacuum, 107, 199–203, 2014.

Gardner, D. J., Oporto, G. S., Mills, R., & Samir, M. A. S. A. Adhesion and surface issues in cel-lulose and nanocellulose. J. Adhes. Sci. Technol., 22(5–6), 545–567, 2008.

Gholamrezaei, S., Salavati-Niasari, M., Bazarganipour, M., Panahi-Kalamuei, M., & Bagheri, S. Novel precursors for synthesis of dendrite-like PbTe nanostructures and investigation of photoluminescence behavior. Adv. Powder Technol., 25(5), 1585–1592, 2014.

Gómez-Guillén, M., Pérez-Mateos, M., Gómez-Estaca, J., López-Caballero, E., Giménez, B., & Montero, P. Fish gelatin: A renewable material for developing active biodegradable films. Trends Food Sci. Technol., 20(1), 3–16, 2009.


Grygiel, K., Wicklein, B., Zhao, Q., Eder, M., Pettersson, T., Bergstroem, L., . . . Yuan, J. Omnidispersible poly (ionic liquid)-functionalized cellulose nanofibrils: Surface grafting and polymer membrane reinforcement. Chem. Commun., 50(83), 12486–12489, 2014.

Habibi, Y. Key advances in the chemical modification of nanocelluloses. Chem. Soc. Rev., 43(5), 1519–1542, 2014.

Hamad, W. On the development and applications of cellulosic nanofibrillar and nanocrystalline materials. Canad. J. Chem. Eng., 84(5), 513–519, 2006.

Hamad, W. Y., & Hu, T. Q. Structure–process–yield interrelations in nanocrystalline cellulose extraction. Canad. J. Chem. Eng., 88(3), 392–402, 2010.

Heßler, N., & Klemm, D. Alteration of bacterial nanocellulose structure by in situ modifica-tion using polyethylene glycol and carbohydrate additives. Cellulose, 16(5), 899–910, 2009.

Hokkanen, S., Repo, E., Westholm, L. J., Lou, S., Sainio, T., & Sillanpää, M. Adsorption of Ni 2+, Cd 2+, PO 4 3− and NO 3− from aqueous solutions by nanostructured microfibrillated cel-lulose modified with carbonated hydroxyapatite. Chem. Eng. J., 252, 64–74, 2014.

Holt, B. L., Stoyanov, S. D., Pelan, E., & Paunov, V. N. Novel anisotropic materials from func-tionalised colloidal cellulose and cellulose derivatives. J. Mater. Chem., 20(45), 10058–10070, 2010.

Hua, K., Carlsson, D. O., Ålander, E., Lindström, T., Strømme, M., Mihranyan, A., & Ferraz, N. Translational study between structure and biological response of nanocellulose from wood and green algae. RSC Adv., 4(6), 2892–2903, 2014.

Isogai, A. Wood nanocelluloses: Fundamentals and applications as new bio-based nanomateri-als. J. Wood Sci., 59(6), 449–459, 2013.

Jafary, R., Khajeh Mehrizi, M., Hekmatimoghaddam, S. h., & Jebali, A. Antibacterial property of cellulose fabric finished by allicin-conjugated nanocellulose. J. Textile Inst., 106(7), 683–689, 2015.

Jaušovec, D., Vogrinčič, R., & Kokol, V. Introduction of aldehyde vs. carboxylic groups to cel-lulose nanofibers using laccase/TEMPO mediated oxidation. Carbohydr. Polym., 116, 74–85, 2015.

Jebali, A., Hekmatimoghaddam, S., Behzadi, A., Rezapor, I., Mohammadi, B. H., Jasemizad, T., . . . Soltani, M. Antimicrobial activity of nanocellulose conjugated with allicin and lysozyme. Cellulose, 20(6), 2897–2907, 2013.

Jiang, F., Dallas, J. L., Ahn, B. K., & Hsieh, Y.-L. 1D and 2D NMR of nanocellulose in aqueous colloidal suspensions. Carbohydr. Polym., 110, 360–366, 2014.

Jin, H., Kettunen, M., Laiho, A., Pynnönen, H., Paltakari, J., Marmur, A., . . . Ras, R. H. Superhydrophobic and superoleophobic nanocellulose aerogel membranes as bioinspired cargo carriers on water and oil. Langmuir, 27(5), 1930–1934, 2011.

Johnson, R. K., Zink-Sharp, A., & Glasser, W. G. Preparation and characterization of hydropho-bic derivatives of TEMPO-oxidized nanocelluloses. Cellulose, 18(6), 1599–1609, 2011.

Jonoobi, M., Harun, J., Mathew, A. P., Hussein, M. Z. B., & Oksman, K. Preparation of cellulose nanofibers with hydrophobic surface characteristics. Cellulose, 17(2), 299–307, 2010.

Jonoobi, M., Harun, J., Mathew, A. P., & Oksman, K. Mechanical properties of cellulose nanofi-ber (CNF) reinforced polylactic acid (PLA) prepared by twin screw extrusion. Compos. Sci. Technol., 70(12), 1742–1747, 2010.

Jonoobi, M., Mathew, A. P., Abdi, M. M., Makinejad, M. D., & Oksman, K. A comparison of modified and unmodified cellulose nanofiber reinforced polylactic acid (PLA) prepared by twin screw extrusion. J. Polym. Environ. 20(4), 991–997, 2012.

Juntaro, J., Pommet, M., Mantalaris, A., Shaffer, M., & Bismarck, A. Nanocellulose enhanced interfaces in truly green unidirectional fibre reinforced composites. Compos. Interf., 14(7–9), 753–762, 2007.


Juntaro, J., Ummartyotin, S., Sain, M., & Manuspiya, H. Bacterial cellulose reinforced polyure-thane-based resin nanocomposite: A study of how ethanol and processing pressure affect physical, mechanical and dielectric properties. Carbohydr. Polym., 87(4), 2464–2469, 2012.

Kaboorani, A., Riedl, B., Blanchet, P., Fellin, M., Hosseinaei, O., & Wang, S. Nanocrystalline cellulose (NCC): A renewable nano-material for polyvinyl acetate (PVA) adhesive. Europ. Polym. J., 48(11), 1829–1837, 2012.

Kalashnikova, I., Bizot, H., Cathala, B., & Capron, I. New Pickering emulsions stabilized by bac-terial cellulose nanocrystals. Langmuir, 27(12), 7471–7479, 2011.

Kardam, A., Raj, K. R., Srivastava, S., & Srivastava, M. Nanocellulose fibers for biosorption of cadmium, nickel, and lead ions from aqueous solution. Clean Technol. Environ. Policy, 16(2), 385–393, 2014.

Kettunen, M., Silvennoinen, R. J., Houbenov, N., Nykänen, A., Ruokolainen, J., Sainio, J., . . . Lindström, T. Photoswitchable superabsorbency based on nanocellulose aerogels. Adv. Funct. Mater., 21(3), 510–517, 2011.

Khalil, H. A., Davoudpour, Y., Islam, M. N., Mustapha, A., Sudesh, K., Dungani, R., & Jawaid, M. Production and modification of nanofibrillated cellulose using various mechanical processes: A review. Carbohydr. Polym., 99, 649–665, 2014.

Khan, A., Khan, R. A., Salmieri, S., Le Tien, C., Riedl, B., Bouchard, J., . . . Lacroix, M. Mechanical and barrier properties of nanocrystalline cellulose reinforced chitosan based nanocomposite films. Carbohydr. Polym., 90(4), 1601–1608, 2012.

Khan, R. A., Dussault, D., Salmieri, S., Safrany, A., & Lacroix, M. Improvement of the mechani-cal and barrier properties of methylcellulose-based films by treatment with HEMA and silane monomers under gamma radiation. Radiat. Phys. Chem., 81(8), 927–931, 2012.

Klemm, D., Schumann, D., Kramer, F., Heßler, N., Hornung, M., Schmauder, H.-P., & Marsch, S. Nanocelluloses as innovative polymers in research and application. Adv. Polym.Sci., 205, 49–96, 2006.

Klemm, D., Schumann, D., Kramer, F., Heßler, N., Koth, D., & Sultanova, B. Nanocellulose materials–different cellulose, different functionality. Paper presented at the Macromolecular Symposia, 2009.

Kloser, E., & Gray, D. G. Surface grafting of cellulose nanocrystals with poly (ethylene oxide) in aqueous media. Langmuir, 26(16), 13450–13456, 2010.

Korhonen, J. T., Hiekkataipale, P., Malm, J., Karppinen, M., Ikkala, O., & Ras, R. H. Inorganic hollow nanotube aerogels by atomic layer deposition onto native nanocellulose templates. ACS Nano, 5(3), 1967–1974, 2011.

Korhonen, J. T., Kettunen, M., Ras, R. H., & Ikkala, O. Hydrophobic nanocellulose aerogels as floating, sustainable, reusable, and recyclable oil absorbents. ACS Appl. Mater. Interf., 3(6), 1813–1816, 2011.

Kramer, F., Klemm, D., Schumann, D., Heßler, N., Wesarg, F., Fried, W., & Stadermann, D. Nanocellulose polymer composites as innovative pool for (bio) material development. Paper presented at the Macromolecular Symposia, 2006.

Lahiji, R. R., Xu, X., Reifenberger, R., Raman, A., Rudie, A., & Moon, R. J. Atomic force micros-copy characterization of cellulose nanocrystals. Langmuir, 26(6), 4480–4488, 2010.

Lam, E., Male, K. B., Chong, J. H., Leung, A. C., & Luong, J. H. Applications of functionalized and nanoparticle-modified nanocrystalline cellulose. Trends Biotechnol., 30(5), 283–290, 2012.

Lee, J.-A., Yoon, M.-J., Lee, E.-S., Lim, D.-Y., & Kim, K.-Y. Preparation and characterization of cellulose nanofibers (CNFs) from microcrystalline cellulose (MCC) and CNF/polyamide 6 composites. Macromol. Res., 22(7), 738–745, 2014.

Lee, S.-Y., Mohan, D. J., Kang, I.-A., Doh, G.-H., Lee, S., & Han, S. O. Nanocellulose reinforced PVA composite films: Effects of acid treatment and filler loading. Fibers Polym., 10(1), 77–82, 2009.


Leitner, J., Hinterstoisser, B., Wastyn, M., Keckes, J., & Gindl, W. Sugar beet cellulose nanofibril-reinforced composites. Cellulose, 14(5), 419–425, 2007.

Lemahieu, L., Bras, J., Tiquet, P., Augier, S., & Dufresne, A. Extrusion of nanocellulose-rein-forced nanocomposites using the dispersed nano-objects protective encapsulation (DOPE) process. Macromol. Mater. Eng., 296(11), 984–991, 2011.

Li, W., Wang, R., & Liu, S. Nanocrystalline cellulose prepared from softwood kraft pulp via ultrasonic-assisted acid hydrolysis. Bioresources, 6(4), 4271–4281, 2011.

Li, W. G., & Xu, Q. H. Preparation and Characterization of Dialdehyde Nanocellulose. Paper pre-sented at the Advanced Materials Research, 2014.

Lin, N., Bruzzese, C. c., & Dufresne, A. TEMPO-oxidized nanocellulose participating as cross-linking aid for alginate-based sponges. ACS Appl. Mater. Interf., 4(9), 4948–4959, 2012.

Lin, N., & Dufresne, A. Nanocellulose in biomedicine: Current status and future prospect. Europ. Polym. J., 59, 302–325, 2014.

Lin, N., Huang, J., & Dufresne, A. Preparation, properties and applications of polysaccharide nano-crystals in advanced functional nanomaterials: A review. Nanoscale, 4(11), 3274–3294, 2012.

Liu, A., & Berglund, L. A. Fire-retardant and ductile clay nanopaper biocomposites based on montmorrilonite in matrix of cellulose nanofibers and carboxymethyl cellulose. Europ. Polym. J., 49(4), 940–949, 2013.

Liu, D., Chen, X., Yue, Y., Chen, M., & Wu, Q. Structure and rheology of nanocrystalline cel-lulose. Carbohydr. Polym., 84(1), 316–322, 2011.

Liu, D., Yuan, X., Bhattacharyya, D., & Easteal, A. Characterisation of solution cast cellulose nanofibre—reinforced poly (lactic acid). Exp. Polym. Lett., 4(1), 26–31, 2010.

Liu, H., Song, J., Shang, S., Song, Z., & Wang, D. Cellulose nanocrystal/silver nanoparticle com-posites as bifunctional nanofillers within waterborne polyurethane. ACS Appl. Mater. Interf., 4(5), 2413–2419, 2012.

Liu, Z., Choi, H., Gatenholm, P., & Esker, A. R. Quartz crystal microbalance with dissipation monitoring and surface plasmon resonance studies of carboxymethyl cellulose adsorption onto regenerated cellulose surfaces. Langmuir, 27(14), 8718–8728, 2011.

Lokanathan, A. R., Nykänen, A., Seitsonen, J., Johansson, L.-S., Campbell, J., Rojas, O. J., . . . Laine, J. Cilia-Mimetic hairy surfaces based on end-immobilized nanocellulose colloidal rods. Biomacromolecules, 14(8), 2807–2813, 2013.

Lu, J., Askeland, P., & Drzal, L. T. Surface modification of microfibrillated cellulose for epoxy composite applications. Polymer, 49(5), 1285–1296, 2008.

Lu, P., & Hsieh, Y.-L. Preparation and properties of cellulose nanocrystals: Rods, spheres, and network. Carbohydr Polym, 82(2), 329–336, 2010.

Lu, T., Li, Q., Chen, W., & Yu, H. Composite aerogels based on dialdehyde nanocellulose and col-lagen for potential applications as wound dressing and tissue engineering scaffold. Compos. Sci. Technol., 94, 132–138, 2014.

Lunz, J. N., Cordeiro, S. B., Mota, J. C. F., & Marques, M. F. Statistical experimental design for obtaining nanocellulose from curaua fiber. Paper presented at the Macromolecular Symposia, 2012.

Ma, H., Zhou, B., Li, H.-S., Li, Y.-Q., & Ou, S.-Y. Green composite films composed of nanocrys-talline cellulose and a cellulose matrix regenerated from functionalized ionic liquid solution. Carbohydr. Polym., 84(1), 383–389, 2011.

Mabrouk, A. B., Salon, M. B., Magnin, A., Belgacem, M., & Boufi, S. Cellulose-based nano-composites prepared via mini-emulsion polymerization: Understanding the chemistry of the nanocellulose/matrix interface. Colloid Surf. A: Physicochemi. Eng. Aspects, 448, 1–8, 2014.

Male, K. B., Leung, A. C., Montes, J., Kamen, A., & Luong, J. H. Probing inhibitory effects of nanocrystalline cellulose: Inhibition versus surface charge. Nanoscale, 4(4), 1373–1379, 2012.


Malho, J.-M., Laaksonen, P. i., Walther, A., Ikkala, O., & Linder, M. B. Facile method for stiff, tough, and strong nanocomposites by direct exfoliation of multilayered graphene into native nanocellulose matrix. Biomacromolecules, 13(4), 1093–1099, 2012.

Masoodi, R., El-Hajjar, R., Pillai, K., & Sabo, R. Mechanical characterization of cellulose nanofi-ber and bio-based epoxy composite. Materials & Design, 36, 570–576, 2012.

Miettunen, K., Vapaavuori, J., Tiihonen, A., Poskela, A., Lahtinen, P., Halme, J., & Lund, P. Nanocellulose aerogel membranes for optimal electrolyte filling in dye solar cells. Nano Energy, 8, 95–102, 2014.

Mihranyan, A., Esmaeili, M., Razaq, A., Alexeichik, D., & Lindström, T. Influence of the nano-cellulose raw material characteristics on the electrochemical and mechanical properties of conductive paper electrodes. J. Mater. Sci., 47(10), 4463–4472, 2012.

Mishra, S. P., Manent, A.-S., Chabot, B., & Daneault, C. Production of nanocellulose from native cellulose–various options utilizing ultrasound. Bioresources, 7(1), 0422–0436, 2011.

Mishra, S. P., Thirree, J., Manent, A.-S., Chabot, B., & Daneault, C. Ultrasound-catalyzed TEMPO-mediated oxidation of native cellulose for the production of nanocellulose: Effect of process variables. Bioresources, 6(1), 121–143, 2010.

Morán, J. I., Alvarez, V. A., Cyras, V. P., & Vázquez, A. Extraction of cellulose and preparation of nanocellulose from sisal fibers. Cellulose, 15(1), 149–159, 2008.

Moritz, S., Wiegand, C., Wesarg, F., Hessler, N., Müller, F. A., Kralisch, D., . . . Fischer, D. Active wound dressings based on bacterial nanocellulose as drug delivery system for octenidine. Int. J. Pharmaceutics, 471(1), 45–55, 2014.

Nakagaito, A., Iwamoto, S., & Yano, H. Bacterial cellulose: The ultimate nano-scalar cellulose morphology for the production of high-strength composites. Appl. Phys. A, 80(1), 93–97, 2005.

Niederberger, M., Garnweitner, G., Krumeich, F., Nesper, R., Cölfen, H., & Antonietti, M. Tailoring the surface and solubility properties of nanocrystalline titania by a nonaqueous in situ functionalization process. Chem. Mater., 16(7), 1202–1208, 2013.

Nimeskern, L., Ávila, H. M., Sundberg, J., Gatenholm, P., Müller, R., & Stok, K. S. Mechanical evaluation of bacterial nanocellulose as an implant material for ear cartilage replacement. J. Mech. Behav. Biomed. Mater., 22, 12–21, 2004.

Nyström, G., Mihranyan, A., Razaq, A., Lindström, T., Nyholm, L., & Strømme, M. A nanocel-lulose polypyrrole composite based on microfibrillated cellulose from wood. J. Phys. Chem. B, 114(12), 4178–4182, 2010.

Olivetti, E. A., Gaustad, G. G., Field, F. R., & Kirchain, R. E. Increasing secondary and renewable material use: A chance constrained modeling approach to manage feedstock quality varia-tion. Environ. Sci. Technol., 45(9), 4118–4126, 2011.

Olsson, R. T., Samir, M. A., Salazar-Alvarez, G., Belova, L., Ström, V., Berglund, L. A., . . . Gedde, U. W. Making flexible magnetic aerogels and stiff magnetic nanopaper using cellulose nano-fibrils as templates. Nat. Nanotechnol., 5(8), 584–588, 2010.

Pahimanolis, N., Hippi, U., Johansson, L.-S., Saarinen, T., Houbenov, N., Ruokolainen, J., & Seppälä, J. Surface functionalization of nanofibrillated cellulose using click-chemistry approach in aqueous media. Cellulose, 18(5), 1201–1212, 2011.

Pahimanolis, N., Salminen, A., Penttilä, P. A., Korhonen, J. T., Johansson, L.-S., Ruokolainen, J., . . . Seppälä, J. Nanofibrillated cellulose/carboxymethyl cellulose composite with improved wet strength. Cellulose, 20(3), 1459–1468, 2013.

Pandey, J. K., Choi, J.-O., Lee, H.-T., Kim, C.-S., Kim, H.-J., Jeon, S., & Ahn, S.-H. Cellulose nanofiber assisted deposition of titanium dioxide on fluorine-doped tin oxide glass. RSC Adv., 4(2), 987–991, 2014.

Paralikar, S. A., Simonsen, J., & Lombardi, J. Poly (vinyl alcohol)/cellulose nanocrystal barrier membranes. J. Membr. Sci., 320(1), 248–258, 2008.


Parikka, K., Leppänen, A.-S., Xu, C., Pitkänen, L., Eronen, P., Österberg, M., . . . Tenkanen, M. Functional and anionic cellulose-interacting polymers by selective chemo-enzymatic car-boxylation of galactose-containing polysaccharides. Biomacromolecules, 13(8), 2418–2428, 2012.

Park, M., Chang, H., Jeong, D. H., & Hyun, J. Spatial deformation of nanocellulose hydrogel enhances SERS. BioChip J., 7(3), 234–241, 2013.

Pei, A., Malho, J.-M., Ruokolainen, J., Zhou, Q., & Berglund, L. A. Strong nanocomposite rein-forcement effects in polyurethane elastomer with low volume fraction of cellulose nanocrys-tals. Macromolecules, 44(11), 4422–4427, 2011.

Pei, A., Zhou, Q., & Berglund, L. A. Functionalized cellulose nanocrystals as biobased nucleation agents in poly (l-lactide)(PLLA)–Crystallization and mechanical property effects. Compos. Sci. Technol., 70(5), 815–821, 2010.

Peng, B., Dhar, N., Liu, H., & Tam, K. Chemistry and applications of nanocrystalline cellulose and its derivatives: A nanotechnology perspective. Canad. J. Chem. Eng., 89(5), 1191–1206, 2011.

Pereda, M., Dufresne, A., Aranguren, M. I., & Marcovich, N. E. Polyelectrolyte films based on chitosan/olive oil and reinforced with cellulose nanocrystals. Carbohydr. Polym., 101, 1018–1026, 2014.

Qamhia, I. I., Sabo, R. C., & Elhajjar, R. F. Static and dynamic characterization of cellulose nano-fibril scaffold-based composites. bioresources, 9(1), 381–392, 2013.

Rajawat, D. S., Kardam, A., Srivastava, S., & Satsangee, S. P. Nanocellulosic fiber-modified car-bon paste electrode for ultra trace determination of Cd (II) and Pb (II) in aqueous solution. Environ. Sci. Pollut. Res., 20(5), 3068–3076, 2013.

Ramimoghadam, D., Bagheri, S., & Abd Hamid, S. B. Biotemplated synthesis of anatase titanium dioxide nanoparticles via lignocellulosic waste material. BioMed Res. Int., 2014.

Rebouillat, S., & Pla, F. State of the art manufacturing and engineering of nanocellulose: A review of available data and industrial applications, 2013.

Rehman, N., de Miranda, M. I. G., Rosa, S. M., Pimentel, D. M., Nachtigall, S. M., & Bica, C. I. Cellulose and nanocellulose from maize straw: An insight on the crystal properties. J. Polym. Environ., 22(2), 252–259, 2014.

Rezayat, M., Blundell, R. K., Camp, J. E., Walsh, D. A., & Thielemans, W. Green one-step synthe-sis of catalytically active palladium nanoparticles supported on cellulose nanocrystals. ACS Sustain. Chem. Eng., 2(5), 1241–1250, 2014.

Rosa, M., Medeiros, E., Malmonge, J., Gregorski, K., Wood, D., Mattoso, L., . . . Imam, S. Cellulose nanowhiskers from coconut husk fibers: Effect of preparation conditions on their thermal and morphological behavior. Carbohydr. Polym., 81(1), 83–92, 2010.

Rueda, L., d’Arlas, B. F., Zhou, Q., Berglund, L. A., Corcuera, M., Mondragon, I., & Eceiza, A. Isocyanate-rich cellulose nanocrystals and their selective insertion in elastomeric polyure-thane. Compos. Sci. Technol., 71(16), 1953–1960, 2011.

Satyamurthy, P., Jain, P., Balasubramanya, R. H., & Vigneshwaran, N. Preparation and charac-terization of cellulose nanowhiskers from cotton fibres by controlled microbial hydrolysis. Carbohydr. Polym., 83(1), 122–129, 2011.

Savadekar, N., & Mhaske, S. Synthesis of nano cellulose fibers and effect on thermoplastics starch based films. Carbohydr. Polym., 89(1), 146–151, 2012.

Shaabani, A., Rahmati, A., & Badri, Z. Sulfonated cellulose and starch: New biodegradable and renewable solid acid catalysts for efficient synthesis of quinolines. Catal. Commun., 9(1), 13–16, 2008.

Shi, Z., Phillips, G. O., & Yang, G. Nanocellulose electroconductive composites. Nanoscale, 5(8), 3194–3201, 2013.


Shopsowitz, K. E., Hamad, W. Y., & MacLachlan, M. J. (2011). Chiral nematic mesopo-rous carbon derived from nanocrystalline cellulose. Angewandte Chem. Int. Ed., 50(46), 10991–10995.

Singha, A.S., Thakur, V.K., 2010a. Mechanical, morphological, and thermal characterization of compression-molded polymer biocomposites. Int. J. Polym. Anal. Charact., 15, 87–97.

Singha, A.S., Thakur, V.K., 2010b. Synthesis, Characterization and Study of Pine Needles Reinforced Polymer Matrix Based Composites. J. Reinf. Plast. Compos., 29, 700–70.

Singha, A.S., Thakur, V.K., 2010c. Synthesis and Characterization of Short Grewia optiva Fiber-Based Polymer Composites. Polym. Compos. 31, 459–47.

Siqueira, G., Bras, J., & Dufresne, A. Cellulose whiskers versus microfibrils: Influence of the nature of the nanoparticle and its surface functionalization on the thermal and mechanical properties of nanocomposites. Biomacromolecules, 10(2), 425–432, 2008.

Siqueira, G., Bras, J., & Dufresne, A. Cellulosic bionanocomposites: A review of preparation, properties and applications. Polymers, 2(4), 728–765, 2010.

Siró, I., & Plackett, D. Microfibrillated cellulose and new nanocomposite materials: A review. Cellulose, 17(3), 459–494, 2010.

Sirviö, J. A., Kolehmainen, A., Visanko, M., Liimatainen, H., Niinimäki, J., & Hormi, O. E. Strong, self-standing oxygen barrier films from nanocelluloses modified with regioselective oxidative treatments. ACS Appl. Mater. Interf., 6(16), 14384–14390, 2014.

Song, J. H., & Sailor, M. J. Functionalization of nanocrystalline porous silicon surfaces with aryllithium reagents: Formation of silicon-carbon bonds by cleavage of silicon-silicon bonds. J. Am. Chem. Soc., 120(10), 2376–2381, 1998.

Soykeabkaew, N., Sian, C., Gea, S., Nishino, T., & Peijs, T. All-cellulose nanocomposites by sur-face selective dissolution of bacterial cellulose. Cellulose, 16(3), 435–444, 2009.

Stevanic, J. S., Joly, C., Mikkonen, K. S., Pirkkalainen, K., Serimaa, R., Rémond, C., . . . Salmén, L. Bacterial nanocellulose-reinforced arabinoxylan films. J. Appl. Polym. Sci., 122(2), 1030–1039, 2011.

Suman, Kardam, A., Gera, M., & Jain, V. A novel reusable nanocomposite for complete removal of dyes, heavy metals and microbial load from water based on nanocellulose and silver nano-embedded pebbles. Environ. Technol., 36(6), 706–714, 2015.

Suopajärvi, T., Koivuranta, E., Liimatainen, H., & Niinimäki, J. Flocculation of municipal waste-waters with anionic nanocelluloses: Influence of nanocellulose characteristics on floc mor-phology and strength. J. Environ. Chem. Eng., 2(4), 2005–2012, 2014.

Suopajärvi, T., Liimatainen, H., Hormi, O., & Niinimäki, J. Coagulation–flocculation treatment of municipal wastewater based on anionized nanocelluloses. Chem.Eng. J., 231, 59–67, 2013.

Suopajärvi, T., Liimatainen, H., Karjalainen, M., Upola, H., & Niinimäki, J. Lead adsorption with sulfonated wheat pulp nanocelluloses. J. Water Proc. Eng., 5, 136–142, 2015.

Surip, S., Wan Jaafar, W., Azmi, N., & Anwar, U. Microscopy observation on nanocellulose from kenaf fibre. Paper presented at the Advanced Materials Research, 2012.

Taokaew, S., Seetabhawang, S., Siripong, P., & Phisalaphong, M. Biosynthesis and characteriza-tion of nanocellulose-gelatin films. Materials, 6(3), 782–794, 2013.

Termehyousefi, A., Bagheri, S., Kadri, N., Elfghi, F. M., Rusop, M., & Ikeda, S. Synthesis of well-crystalline lattice carbon nanotubes via neutralized cooling method. Mater.Manufactu. Proc., 30(1), 59–62, 2015.

TermehYousefi, A., Bagheri, S., Shinji, K., Rouhi, J., Rusop Mahmood, M., & Ikeda, S. Fast synthesis of multilayer carbon nanotubes from camphor oil as an energy storage material. BioMed. Res. Int., 2014.

Tingaut, P., Zimmermann, T., & Sèbe, G. Cellulose nanocrystals and microfibrillated cellulose as building blocks for the design of hierarchical functional materials. J. Mater. Chem., 22(38), 20105–20111, 2012.


Thakur, V.K., Singha, A.S., Thakur, M.K., Ecofriendly biocomposites from natural fibers: Mechanical and weathering study. Int. J. Polym. Anal. Charact., 18, 64–72, 2013a.

Thakur, V.K., Singha, A.S., Thakur, M.K., Fabrication and physico-chemical properties of high-performance pine needles/green polymer composites. Int. J. Polym. Mater. Polym. Biomater., 62, 226–230, 2013b.

Thakur, V.K., Singha, A.S., Thakur, M.K., Natural cellulosic polymers as potential reinforcement in composites: physicochemical and mechanical studies. Adv. Polym. Technol., 32, E427–E435, 2013c.

Thakur, V.K., Singha, A.S., Thakur, M.K., Synthesis of natural cellulose–based graft copolymers using methyl methacrylate as an efficient monomer. Adv. Polym. Technol. 32, E741–E748, 2013d.

Thakur, V.K., Thakur, M.K., Gupta, R.K., Graft copolymers from natural polymers using free radical polymerization. Int. J. Polym. Anal. Charact. 18, 495–503, 2013e.

Thakur, V.K., Thakur, M.K., Singha, A.S., Free radical–induced graft copolymerization onto natural fibers. Int. J. Polym. Anal. Charact., 18, 430–438, 2013f.

Thakur, V.K., Grewell, D., Thunga, M., Kessler, M.R., Novel composites from eco-friendly Soy flour/SBS triblock copolymer. Macromol. Mater. Eng., 299, 953–958, 2014a.

Thakur, V.K., Thakur, M.K., Gupta, R.K., Graft copolymers of natural fibers for green compos-ites. Carbohydr. Polym., 104, 87–93, 2014b.

Thakur, V.K., Singha, A.S., Thakur, M.K., Pressure induced synthesis of ea grafted Saccaharum cilliare fibers. Int. J. Polym. Mater. Polym. Biomater., 63, 17–22, 2014c.

Thakur, V.K., Thakur, M.K., Gupta, R.K., Review: Raw natural fiber–based polymer composites. Int. J. Polym. Anal. Charact., 19, 256–271, 2014d.

Thakur, V. K., & Voicu, S. I. Recent advances in cellulose and chitosan based membranes for water purification: A concise review. Carbohydr. Polym., 146, 148, 2016.

Tomé, L. C., Fernandes, S. C., Perez, D. S., Sadocco, P., Silvestre, A. J., Neto, C. P., . . . Freire, C. S. The role of nanocellulose fibers, starch and chitosan on multipolysaccharide based films. Cellulose, 20(4), 1807–1818, 2013.

Viet, D., Beck-Candanedo, S., & Gray, D. G. Dispersion of cellulose nanocrystals in polar organic solvents. Cellulose, 14(2), 109–113, 2007.

Walther, A., Timonen, J. V., Díez, I., Laukkanen, A., & Ikkala, O. Multifunctional high-per-formance biofibers based on wet-extrusion of renewable native cellulose nanofibrils. Adv. Mater., 23(26), 2924–2928, 2011.

Wang, M., Olszewska, A., Walther, A., Malho, J.-M., Schacher, F. H., Ruokolainen, J., . . . Osterberg, M. Colloidal ionic assembly between anionic native cellulose nanofibrils and cat-ionic block copolymer micelles into biomimetic nanocomposites. Biomacromolecules, 12(6), 2074–2081, 2011.

Wang, N., Ding, E., & Cheng, R. Preparation and liquid crystalline properties of spherical cel-lulose nanocrystals. Langmuir, 24(1), 5–8, 2008.

Wesarg, F., Schlott, F., Grabow, J., Kurland, H.-D., Heßler, N., Kralisch, D., & Müller, F. A. In situ synthesis of photocatalytically active hybrids consisting of bacterial nanocellulose and ana-tase nanoparticles. Langmuir, 28(37), 13518–13525, 2012.

Wu, C.-N., Saito, T., Fujisawa, S., Fukuzumi, H., & Isogai, A. Ultrastrong and high gas-barrier nanocellulose/clay-layered composites. Biomacromolecules, 13(6), 1927–1932, 2012.

Wu, Q., Henriksson, M., Liu, X., & Berglund, L. A. A high strength nanocomposite based on microcrystalline cellulose and polyurethane. Biomacromolecules, 8(12), 3687–3692, 2007.

Xie, K., Gao, X., & Zhao, W. Thermal degradation of nano-cellulose hybrid materials contain-ing reactive polyhedral oligomeric silsesquioxane. Carbohydr. Polym., 81(2), 300–304, 2010.

Xiong, R., Zhang, X., Tian, D., Zhou, Z., & Lu, C. Comparing microcrystalline with spherical nanocrystalline cellulose from waste cotton fabrics. Cellulose, 19(4), 1189–1198, 2012.


Yang, H., Tejado, A., Alam, N., Antal, M., & van de Ven, T. G. Films prepared from electrosteri-cally stabilized nanocrystalline cellulose. Langmuir, 28(20), 7834–7842, 2012.

Yang, W., Baker, S. E., Butler, J. E., Lee, C.-s., Russell, J. N., Shang, L., . . . Hamers, R. J. Electrically addressable biomolecular functionalization of conductive nanocrystalline diamond thin films. Chem. Mater., 17(5), 938–940, 2005.

Zaman, M., Xiao, H., Chibante, F., & Ni, Y. Synthesis and characterization of cationically modi-fied nanocrystalline cellulose. Carbohydr. Polym., 89(1), 163–170, 2012.

Zander, N. E., Dong, H., Steele, J., & Grant, J. T. Metal cation cross-linked nanocellulose hydro-gels as tissue engineering substrates. ACS Appl. Mater. Interf., 6(21), 18502–18510, 2014.

Zhang, J., Elder, T. J., Pu, Y., & Ragauskas, A. J. Facile synthesis of spherical cellulose nanopar-ticles. Carbohydr. Polym., 69(3), 607–611, 2007.

Zhang, R., Yu, S., Chen, S., Wu, Q., Chen, T., Sun, P., . . . Ding, D. Reversible Cross-linking, microdomain structure, and heterogeneous dynamics in thermally reversible cross-linked polyurethane as revealed by solid-state NMR. J. Phys. Chem. B, 118(4), 1126–1137, 2014.

Zhang, S., Winestrand, S., Chen, L., Li, D., Jonsson, L. J., & Hong, F. Tolerance of the nanocel-lulose-producing bacterium gluconacetobacter xylinus to lignocellulose-derived acids and aldehydes. J. Agricult. Food Chem., 62(40), 9792–9799, 2014.

Zhao, H., Kwak, J. H., Zhang, Z. C., Brown, H. M., Arey, B. W., & Holladay, J. E. Studying cel-lulose fiber structure by SEM, XRD, NMR and acid hydrolysis. Carbohydr. Polym., 68(2), 235–241, 2007.

Zhen, W. J. Study on nanocellulose/starch composites. Paper presented at the Advanced Materials Research, 2011.

Zhou, C., & Wu, Q. Recent development in applications of cellulose nanocrystals for advanced poly-mer-based nanocomposites by novel fabrication strategies: INTECH Open Access Publisher, 2012.

Zhou, P., Wang, H., Yang, J., Tang, J., Sun, D., & Tang, W. Bacteria cellulose nanofibers sup-ported palladium (0) nanocomposite and its catalysis evaluation in Heck reaction. Indust. Eng. Chem. Res., 51(16), 5743–5748, 2012.

Zimmermann, K. A., LeBlanc, J. M., Sheets, K. T., Fox, R. W., & Gatenholm, P. Biomimetic design of a bacterial cellulose/hydroxyapatite nanocomposite for bone healing applications. Mater. Sci. Eng.: C, 31(1), 43–49, 2011.

Documents

Nanocrystalline Cellulose: Green, Multifunctional and ... · Nanocrystalline Cellulose: Green, Multifunctional and Sustainable ... 524 Handbook of Composites from Renewable ... Treated