PhD Confirmation_20130522 NOanimationRev [Compatibility Mode]

Natural Fibre Composites:

Manufacture and Characterisation

of Micro Cellulose Fibre Composites

PhD Confirmation of Candidature

22.05.2013 Angelica Legras

1

2012 CRC-ACS Commercial-In-Confidence

Outline

2

Background

Natural Fibres for Composites

UQ / CRC-ACS collaboration

Scope of work

Alternative milling processes: impact on fibre properties

Digital image processing for fibre characterisation

Design of Experiment to optimise extrusion process

Compound characterisation and benchmarking

First results &

Discussions

Impact of milling on kenaf fibres properties

Fibre characterisation with automated image analysis

Extrusion of bast fibres based thermoplastic compounds

OutlookOutlook

Thesis plan

Time schedule


Natural Fibres

Cellulose based fibres: multiple origins, multiple properties

Fibre properties as received = f(origin, crop conditions, processing)

3

Background Scope of work First results & Discussions Outlook

Plant fibres

Cellulose fibres

Bast

FlaxJute

HempKenafRamie

Leaf Seed/ fruit Grass Wood

AbacaBanana

HenequenPineapple

Sisal

CoconutCotton

CoirKapok

BambooBarleyCornOatRice

HardwoodSoftwood

* Seed stock

* Variety

* Geography

* Climate

* Chemical input

* Harvest

* Retting

* Decortication

* Pre-treatment

Figure 1: Various origins of cellulose fibres


Natural Fibres

Physical structure of bast fibres: 3D layer composite

Elementary fibre = multiple layers of crystalline microfibrils (based on cellulose) embedded in

amorphous lignin/hemicellulose matrix >> composite structured

4


Figure 3: Structure of an elementary fibreFigure 2 :Kenaf stem cross section

(A) Photograph under white light with a dissecting microscope

(B) Photograph UV epifluorescence

(C) Scheme of phloem fibre bundle

20 m 20 m20 m


Natural Fibres

Chemical composition: variable proportions of cellulose, hemi-cellulose, lignin, pectin, waxes

and water soluble components.

Cellulose

- Crystalline linear polymer of D-anhydroglucoypranose units linked by -1,4-glycosidic bonds

- Each type of cellulose has a proper cell geometry (a-b-c, ) => define fibre mechanical

properties

5


Figure 4: Molecular structure of

cellulose

n-2

Figure 5: Orientation of molecular

chains (crystalline region)


Natural Fibres

Hemi cellulose

- Branched groups of polysaccharides

- NOT cellulose:

* contains various sugar units (constituents vary from plant to plant)

* branched polymer

* DP hemicellulose < DP cellulose (100x)

Lignin: complex hydrocarbon polymer made of aliphatic and aromatic constituents

Pectin: heteropolysaccharide. Soluble in water after chemical treatment (eg. Alkali treatment)

Waxes: made of various alcohols. Can be extracted with organic solutions. Not soluble in

water neither acids

6


Figure 6: Hemicellulose


Natural Fibre Composites (NFCs)

Potential as reinforcement fibres : alternative to glass fibre composites (GFCs)

Advantages NFs vs. GFs

* Cost-efficient

* Low carbon footprint (biodegradable/ renewable)

* Few risk for health

* Few abrasive (processing, recycling)

* Good acoustic properties

* Good specific properties:

7


Table 1 [1]:



Potential as fillers: alternative to wood fibre composites (WFCs)

Advantages NFs vs. WFs

* Similar or higher yield (per area/per annum)

* Typically better performances

8


Table 2 DATA WOOD/ DATA Bast

fibres REF:

Figure 7: Stem yield of annual plants and crops vs. popular wood



Main issues

* Batch-to-batch heterogeneity, fibre quality variable

> Control NF properties to set up processing parameters, to predict mechanical properties

* Complex fibre/matrix interfacial interactions (inherent incompatibility NF hydrophilic with

hydrophobic TP matrix)

> Achieve full potential as reinforcement fibre

*Low thermal stability restrictive for compounding

> Enable to widen NF/ TP, NF/Thermosets composites

* High moisture sensitivity

> Ensure compound stability

9



UQ/ CRC-ACS collaboration

Agronomy

Seed stock

Growing plant

Harvest

Decortication/ Retting

Raw materials

Fibre extraction

Fibre characterisation

Processing of waste products

Intermediates

Fibre treatment

Fabrics

Compounding to pellets

Establish material performance database

Products

Design building product

Manufacture product

10

Kenaf

Kenaf

Hemp

Noil hemp/ PP

P1.1 WP2 Enhanced Short Fibre Biocomposites



UQ/ CRC-ACS collaboration

11

P1.1 WP2 Enhanced Short Fibre Biocomposites

Supplier

Kenaf bast fibres Ecofibre Industries Operations Pty. Ltd. [24] CACM Uni Auckland

Hemp bast fibres Ecofibre Industries Operations Pty. Ltd.

Hemp hurd Ecofibre Industries Operations Pty. Ltd.

Supplier

Commodity thermoplastics

Polypropylene (TBD)

Bio resin Bio sourced/ Biodegradable (TBD)

Fibres Matrix



Issue : Impact of fibre processing

12

Processing Level Industry involved

0 Crop (field) AGRONOMY

Harvest

1 Stems TEXTILE/ PULP & PAPER

RettingBiological

Chemical

2 Retted stalks (fragmented) TEXTILE/ PULP & PAPER

DecorticationAutomatic

Manual

3 Bast fibres & woody parts TEXTILE/ PULP & PAPER


2012 CRC-ACS Commercial-In-Confidence 13

Processing Level Industry involved

0 Crop (field) AGRONOMY

1 Stems TEXTILE/ PULP & PAPER

2 Retted stalks (fragmented) TEXTILE/ PULP & PAPER

3 Bast fibres & woody parts TEXTILE/ PULP & PAPER

Chemical treatment

Physical treatment

Traditional scenarios Alternative scenarios

Milling

Chemically treated fibresPhysically treated fibres

Processed fibres for reinforcement/ filler application

NATURAL FIBRE COMPOSITES4

Issue : Impact of fibre processing

$$

Impact fibre properties??Eco-friendly?



Issue : Mechanical behaviour


Brief review : Mechanical behaviour in short fibre composites

Single fibre in matrix under tensile load (elastic behaviour, full transfer):

lc = Critical length

length above which the fibre undergoes

tensile failure and under which shear

failure occurs at the interface

Figure 8: Strain distribution in a system (short single fibre, matrix) under load

/2


Issue : Mechanical behaviour


Brief review : Mechanical behaviour in short fibre composites

Matrix Fibre () /

Epoxy Carbon 0.2 35

Polycarbonate Carbon 0.7 105

Polyester Glass 0.5 40

Polypropylene Glass 1.8 140

Alumina SiC 0.005 10

Critical Aspect RatioCritical length

Table 2 [2]:


Issue : Extrusion of NFCs

Compounding of NFCs

Manufacturing: extrusion + ancillary equipment to produce pellets:

- Technique well established for GFCs but few research for NFCs

- Influence of processing parameters?

>> Screw speed, screw configuration, barrel temperature, feeding zone.


Figure 9: Compounding process by extrusion and pelletizing


Objectives of ResearchFibre extraction techniques

Select alternative milling techniques (mechanical processing)

Analyse the effect of milling on fibre properties (fibre separation, fibre length, surface damage, defects)


Develop a novel technique to characterise the fibres by automated image analysis (criteria: setup quick and easy, large sampling, acceptable error on the data)

Optimisation of extrusion process

Design a series of experiments using the Taguchi approach (fractional factorial)

Analyse the influence of defined factors on the compound properties using ANOVA

Characterisation of natural fibre biocomposites

Define a characterisation plan according to P1.1 teamwork general directions

Select suitable characterisation techniques

Benchmarking: compare the biocomposites properties with wood fibre and glass fibre composites properties



Alternative milling processes

Aim: Compare various milling techniques & investigate impact on the fibre structure

Milling techniques:


Principle/ Interest Location Funding

High speed cyclone (Aximill [25])

Separation by air flow i.e. no agglomeration / large volume capacity/ easy to process

Aximill, Victoria CRC-ACS

Hammer mill Dry mill/ easy to process Sustainable Minerals Institute, UQ

/

High Energy Ball Mill (HEBM)

Dry or wet mill: batch/ temperature and milling time variable

Chemical Engineering School, UQ

/

Hammer Mill

HEBM

Aximill


Alternative milling processes

Aim: Compare various milling techniques & investigate impact on the fibre structure

Strategy:

Results to be compared with chemical treated fibres (PhD Student P1.1)


Effect studied Criterion Equipment

Fibre separation Fibre diameter Automated image analysis technique

Mechanism(s) involved OM, SEM Impact on fibre

length Fibre length distribution Automated image analysis technique

Fracture mechanism(s) OM, SEM Impact on fibre

surface Surface topography SEM, EDX

Surface composition XPS/ FTIR

Fibre damage Defect distribution along the fibres (kinks, nodes etc.) X-polarised light OM/ confocal microscopy, SEM



Aim: Develop a low-cost and fast fibre characterisation technique

Criteria:

- Wide length range: macro to micro fibres

- Large amount: more than 1000 elements

- Set up quick & easy

Method:

- Step 1: Image acquisition with a high resolution flatbed scanner (9600dpi)

- Step 2: Digital image processing via algorithms programmed in Matlab

Benchmarking:

- Commercial techniques (WFs, pulp & paper)

- Potential laboratory application


AR = Length/ Diameter


Design of Experiment for extrusion

Aim: Study influence of processing parameters to optimise extrusion process for NFCs

Design of Experiment (DOE) using the Taguchi approach :

- Study the influence of the main factors only

- Standards for defined factors & levels : orthogonal arrays

- Full factorial analysis/ fractional factorial analysis


Experiments

Column

1 2 3 4 5 6 7

1 1 1 1 1 1 1 1

2 1 1 1 2 2 2 2

3 1 2 2 1 1 2 2

4 1 2 2 2 2 1 1

5 2 1 2 1 2 1 2

6 2 1 2 2 1 2 1

7 2 2 1 1 2 2 1

8 2 2 1 2 1 1 2

Table 3 [3]: L8 (27) orthogonal array


Design of Experiment for extrusion

Aim: Study influence of processing parameters to optimise extrusion process for NFCs

Strategy:


Task Approach Equipment/ Resources Location

DOE Definition of the factors and levels

Taguchi fractional factorial

ANOVA

Team experience (University of Auckland, USQ), literature review Handbook Extrusion : The Definitive Processing Guide and Handbook [14] Handbook Design of experiments using the Taguchi approach [21] Undergraduate Student (Thesis)

UQ

Extrusion trials

According to DOE

Twin screw extruder

Side feeder(s) Raw material (fibres/coupling agent/ matrix)

Griffith University

Chemical Engineering/

AIBN,UQ


Compound characterisation

Aim: Gain understanding regarding fibre behaviour in an extrusion process

Scientific questions to be answered:

- Can extrusion principles used in the extrusion of GFCs be applied ?

- How do fibre with such a complex surface behave in an extrusion process?

- How does the fibre physiology affect final properties?

Strategy:


Fibre behaviour Criterion Equipment

Fibre distribution in the matrix

Fibre volume fraction TBD (Micro-CT scan or Nano-CT scan) Fibre aspect ratio Automated image analysis

Fibre orientation Flow patterns TBD (Micro-CT scan or Nano-CT scan) Fibre/matrix interfacial

properties Fracture surface OM/ SEM

Fibre properties Surface composition XPS/ FTIR Crystallinity XRD Thermal degradation TGA- DTA Defects X-polarised light OM/ confocal microscopy, SEM


Comparison of milling techniques

Experimental details


Input Parameters Trials

High speed cyclone (AxiMill)

- Fibre length: chopped fibres ca. 5 to 10 cm

- Processing level: raw fibres

- Large mill/small mill (chamber 1 m/0.25 m) - Rotor speed (30 Hz to 60 Hz) - Selection output drum bag (coarse/fine/extra fine)

- Kenaf, hemp, hemp hurd

- ca. 30 different batches

Hammer mill - Fibre length: chopped fibres ca.0.5 cm

- Processing level: raw fibres

- Rotor Speed (potentiometer) - Mesh grid ( 0.5mm/1mm/2mm)

- Kenaf, hemp, hemp hurd

- 1 batch for each type of fibre

High Energy Ball Mill (HEBM)

- Fibre length: chopped fibres ca. 2 cm

- Processing level: fibres soaked overnight in distilled water

- 400mL batch

- Milling time

- ZrO2 balls ( 0.4mm, 1mm) - Temperature (24C to 50C) - Rotor speed (1000 rpm to 3500 rpm)

- Kenaf in distilled water

- Fibre content: 20 gr/L, 8 gr/L (2 batches) - Miling time: 10 min, 1hour


Comparison untreated fibres: SEM analysis

25



Kenaf raw (Ecofibre) Kenaf raw (CACM)

- Rough surface but few apparent defects

- No fibrillation

- Bundles of technical fibres ( ca. 70-100 m)

- Surface seems quite smooth

- Some defects (kinks, nodes)

- Some fibrillation

- bundles of technical fibres ( ca. 50-80 m)

General observation: fibre cross section not circular, rather hexagonal.

Surface, shape: Fibres Ecofibre # fibres CACM >> to be considered for future interpretation of experimental data


Comparison of milled fibres: SEM analysis

26



Kenaf Aximill Kenaf Hammer mill Kenaf HEBM

- Regular patterns on the surface

- ca. 70-100 m : no obvious

separation

- Fibrillation

- Regular patterns on the surface

- ca. 70-100 m : no obvious

separation

- Few fibrillation

- Surface degradation

- Heterogeneity: bundles, technical

fibres


Comparison of milled fibres: SEM analysis

27



Kenaf Aximill Kenaf Hammer mill Kenaf HEBM

- Fracture not always complete

- Fracture by shear, bending, twist

- Apparent defects (kinks)

- Fracture mostly complete, sharp

fractures

- Few apparent defects

- Fracture not obvious

- Initiation fracture by bending

- Fibres peeled away

- Viscoelastic/plastic deformation of

the matrix binding the fibres


Low-cost characterisation technique

Digital image processing via algorithms in Matlab

Step 1: Selection of fibres according to criteria (size, shape)


65mm

120mmKenaf (Ecofibre)



Digital image processing via algorithms in Matlab

Step 2: Estimation of length & diameter via ellipse fitting


Kenaf (Ecofibre)

Length (m)

Diameter (m)

N

o

.

f

i

b

r

e

s

N

o

.

f

i

b

r

e

s

MajorAxisLength

MinorAxisLength

Ellipse fitting



OUTPUT: Aspect Ratio (AR) distribution


EK9 Kenaf Ecofibre

No. fibres

AR



Comparison with other techniques:

Aspects to be improved:

Complex configurations not taken into account:

Ellipse fitting: length underestimated & diameter overestimated


Chemical treated fibres (KFTHA)

Scanner + Matlab

algorithm

FiberScan

FiberLab OM + ImageTool software

Number of elements

1788 +6000 +6000 50

Mean length (m) 1170 794 280 1750 2312 627

Mean diameter (m)

324 334 / 17.3 13 3

Aspect ratio 5 4 / 102 178

kinkedfibre

loop


Extrusion of NFCs

Extrusion trials:

- Kenaf/PP: (40:60) wt% ratio

- Kenaf/MAPE/HDPE: (40:3:57) wt% ratio

- Side feeding of kenaf fibres btw the mixing zones


1st mixing zone2nd mixing zone

Fibre side feeding Current configuration for extrusion with the PRISM Eurolab16 TSE (25:1)

Feeder 1: Resin

Feeder 2: Fibres

39 cm


Extrusion of NFCs

Extrusion trials:

- Calibration of the feeders with pellets, powder resin and fibres

- Extrusion of strips show promising results


Strip die: 25x2mm

Kenaf/ MAPE/ HDPE (40:57:3)

1

0

c

m

Kenaf/ PP (20:80)


Outlook


Fibre extraction techniques

i. Select alternative milling techniques (mechanical processing)

ii. Analyse the effect of milling on fibre properties (fibre separation, fibre length, surface damage, defects)

100%

40%


i. Develop a novel technique to characterise the fibres by automated image analysis (criteria: setup quick and easy, large sampling, acceptable error on the data) 60%

Publication opportunity: - Comparison of the effect of alternative milling techniques on bast fibre properties

Publication opportunity: - Development of a novel technique based on automated image analysis to characterise short fibre aspect ratio- Characterisation of short bast fibres with automated image analysis


Outlook


Optimisation of extrusion process

i. Design a series of experiments using the Taguchi approach (fractional factorial)

ii. Analyse the influence of defined factors on the compound properties using ANOVA

0%

0%

Publication opportunity: - Optimisation of the extrusion process for natural fibres compounding using Taguchi approach

Characterisation of natural fibre biocomposites

i. Define a characterisation plan according to P1.1 teamwork general directions

ii. Select suitable characterisation techniques

iii. Benchmarking: compare the biocomposites properties with wood fibre and glass fibre composites properties

0%

0%

0%

Thanks for your attention

36


References Tables

[1]: Summerscales, J., N. P. J. Dissanayake, A. S. Virk & W. Hall (2010) A review of bast fibres and their composites. Part 1

Fibres as reinforcements. Composites Part A: Applied Science and Manufacturing, 41, 1329-1335.

[2]: F.L. Matthews, R.D. Rawlings, Composite materials: engineering and science, CRC Press, Cambridge, England, 1999.

[3]: R.K. Roy, Design of experiments using the Taguchi approach: 16 steps to product and process improvement, Wiley, New

York, 2001.

37


References Figures

Figure 1: Wallenberg F. T., Weston N., (2004) Natural fibres, plastics and composites. Kluwer Academic Publishers.

Figure 2: Ayre, B. G. S., Kevin; Chapman, Kent D.; Webber III, Charles L.; Dagnon, Koffi L.; DSouza, Nandika A. (2009)

Viscoelastic Properties of Kenaf Bast Fiber in Relation to Stem Age. Textile Research Journal, 79, 973-980.

Figure 3: Alcock M. et al., Plant Fibre Biocomposites State of the Art Report. TR 11030, CRC ACS.

Figure 4: http://www.uq.edu.au/_School_Science_Lessons/16.3.1.7ach.GIF

Figure 5: Bledzki, A. K. & J. Gassan (1999) Composites reinforced with cellulose based fibres. Progress in Polymer Science, 24,

221-274.

Figure 6: Hemicellulose molecule: http://www.bio.miami.edu/dana/226/226F07_3print.html

Figure 7: A.H. Grigoriou, G.A. Ntalos, The potential use of Ricinus communis L. (Castor) stalks as a lignocellulosic resource for

particleboards, Industrial Crops and Products, 13 (2001) 209-218.

Figure 8: F.L. Matthews, R.D. Rawlings, Composite materials: engineering and science, CRC Press, Cambridge, England, 1999.

Figure 9: H.F. Giles Jr, E.M. Mount Iii, J.J.R. Wagner, Extrusion : The Definitive Processing Guide and Handbook: The Definitive

Processing Guide and Handbook, William Andrew, Burlington, 2004.

Picture kenaf stem, slide 10 : http://ecofibre.com.au/other-bast-crops/

Picture house, slide 10: http://www.theaustralian.com.au/news/stilts-the-one-in-queensland/story-e6frgdt6-1111114499775

Logo BCA, slide 10: http://www.abcb.gov.au/

Picture HEBM, slide 18: http://www.netzsch-grinding.com/

Picture Aximill, slide 18: http://aximill.com/

Picture field, slide 36: http://www.mastersoflinen.com/fre/technique/16-textile

38


References

[1] J. Summerscales, N.P.J. Dissanayake, A.S. Virk, W. Hall, A review of bast fibres and their composites. Part 1 Fibres as

reinforcements, Composites Part A: Applied Science and Manufacturing, 41 (2010) 1329-1335.

[2] A.K. Mohanty, M. Misra, L.T. Drzal, Surface modifications of natural fibers and performance of the resulting biocomposites: An

overview, Composite Interfaces, 8 (2001) 313-343.

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particleboards, Industrial Crops and Products, 13 (2001) 209-218.

[4] G. Chinga-Carrasco, O. Solheim, M. Lenes, A. Larsen, A method for estimating the fibre length in fibre-PLA composites, Journal

of microscopy, 250 (2013) 15-20.

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certain fibre quality traits, Industrial Crops and Products, 13 (2001) 49-56.

[6] B.G.S. Ayre, Kevin; Chapman, Kent D.; Webber III, Charles L.; Dagnon, Koffi L.; DSouza, Nandika A., Viscoelastic Properties of

Kenaf Bast Fiber in Relation to Stem Age, Textile Research Journal, 79 (2009) 973-980.

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39


References

[11] F.L. Matthews, R.D. Rawlings, Composite materials: engineering and science, CRC Press, Cambridge, England, 1999.

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by a water fibre treatment and drying cycle, Industrial Crops and Products, 39 (2012) 31-39.

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Composites Science and Technology, 70 (2010) 995-999.

[14] H.F. Giles Jr, E.M. Mount Iii, J.J.R. Wagner, Extrusion : The Definitive Processing Guide and Handbook: The Definitive

Processing Guide and Handbook, William Andrew, Burlington, 2004.

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treatment and matrix modification, Composites Part A: Applied Science and Manufacturing, 39 (2008) 979-988.

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York, 2001.

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[24] E.I. Operations, http://ecofibre.com.au/, in, 2010.

[25] Aximill, http://aximill.com/, in, 2013.

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Documents

PhD Confirmation_20130522 NOanimationRev [Compatibility Mode]