Carbon Fibers, Multi-functional Textile Fibers,

Meso-porous Carbon

Opportunities for lignin and cellulose nano crystals

(based on examples of polymer/carbon nanotube studies)

Satish Kumar

School of Materials Science and Engineering

Georgia Institute of Technology

Atlanta, GA 30332-0295

satish.kumar@gatech.edu

1

Institute of Paper Science and Technology April 18, 2013

Carbon Fibers

2

1960 – Start of Carbon Fiber Research in Japan, UK, and USA.

Carbon Fiber market is growing at about 10 - 12% per year.

Carbon fibers have been produced from Rayon, poly(acrylonitrile) (PAN), and

from petroleum pitch.

Early carbon fibers were produced from Rayon, and these rayon based carbon

fibers are no longer commercially produced.

Currently carbon fibers are predominantly made from PAN.

PAN based carbon fiber tensile strength: 3 to 6 GPa, Tensile modulus: 200 to

500 GPa.

M. L. Minus and S. Kumar, JOM, 57, 52-58 (2005)

Lignin based Carbon Fibers

3

• Research driven by the desire to produce a low cost carbon fiber.

• Tensile strength in the range of 0.5 to 1 GPa and tensile modulus in the range of

35 to 40 GPa demonstrated for the lignin based carbon fibers. (Clemson

University, ORNL, American Chemical Society, New Orleans, April 2013).

• Due to high degree of chemical crosslinking, lignin based carbon fibers exhibit

very little or no molecular orientation, thus resulting in relatively low modulus.

• Carbon fibers are also being made from the PAN/ lignin blend fibers (DOE project

at Zoltek).

• For automotive application, there is a need to bring the carbon fiber cost down to

about $5/lb (DOE target). At this cost, carbon fiber with a tensile strength of about

2 GPa and tensile modulus of about 175 GPa would be sufficient.

Fiber and Carbon Fiber Processing Facilities at Georgia Tech

4

• Single filament, single component and bi-component melt, solution, and gel

spinning. Scale - about 100 ml polymer solution or about 100 g polymer melt can

be spun on these lines.

• 100 filament single component and bi-component dry-jet solution and gel

spinning and multi-zone drawing line. Polymer solutions (at the scale of 1 to 6

liters) can be spun on this line. Five, 100 filament tows can be combined to

make a 500 multifilament tow. This facility is in class 1000 clean-room.

• About 70 ft long continuous carbonization line with multi-zone stabilization and

multi-zone carbonization capability. This line is also located in class 1000 clean-

room. Continuous carbonization of 100 to 6000 filaments has been

demonstrated on this line.

• Well equipped fiber characterization and testing facility.

n

N

O O

N

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 0.5 1 1.5 2 2.5 3

Strain (%)

Str

es

s (

GP

a)

PBO

PBO/SWNT(90/10)PBO

PET/CNF

S Kumar, TD Dang, FE Arnold, AR Bhattacharyya, BG Min, XF Zhang, RA Vaia, C Park, WW Adams, RH Hauge, RE Smalley,

S Ramesh, PA Willis, Macromolecules, 35(24), 9039 (2002).

H Ma, J Zeng, ML Realff, S Kumar, DA Schiraldi, Composites Science and Technology, 63, 1617 (2003).

SWNT

5

Raman Spectroscopic evidence of load transfer from matrix to CNT

- PVA/SWNT films

• Well dispersed and exfoliated SWNTs in PVA.

• Significant increase in tensile properties.

Stress-strain curves

2566

2568

2570

2572

2574

2576

2578

2580

2582

0 10 20 30 40 50

Strain (%)

D*

ban

d p

eak p

osit

ion

(cm

-1)

Raman D* band shift with strain

300 400 500 600 700 800 900

Wavelength (nm)

Ab

so

rba

nc

e (

a. u

)

a

b

c

d

UV-VIS Spectra

Raman D* band shift with strain

(a) PVP/SDS/SWNT aqueous dispersion

(b) PVA/PVP/SDS/SWNT film (1 wt% SWNT)

(c) PVA/PVP/SDS/SWNT film (5 wt%)

(d) PVA/SWNT film (1 wt%)

XF Zhang, T Liu, TV Sreekumar, S Kumar, VC Moore, RH Hauge, RE Smalley, Nano Lett, 3(9), 1285 (2003). 6

Individual CNT in PAN matrix

PAN/CNT – early developments

At 10% CNT, 50 times increase in modulus at 140 oC, and 40 oC increase in Tg

5 nm

TV Sreekumar, T Liu, BG Min, H Guo, S Kumar, RH Hauge, RE Smalley, Advanced Materials, 16(1), 58 (2004). 7

PAN/SWNT (60/40) Film

– Electrical conductivity (~104 S/m) – comparable to

electrically conducting polymers such as polythiophene,

polypyrrole, and polyaniline.

– Tensile strength (100 MPa) and modulus (11 GPa) higher

than that of SWNT bucky paper or the polymer, and

comparable to those of the engineering thermoplastics

– Films exhibit high degree of dimensional stability (CTE <2

ppm/oC)

– Polymer molecular motion above glass transition

temperature is dramatically suppressed.

– Low density (~1 g/cm3)

– Thermally stable and exhibits Chemical resistance

0.0

0.1

0.2

0.3

0.4

0.5

0.6

30 50 70 90 110 130 150 170

Temperature (oC)

tanδ

PAN/SWNT (60/40) film

Control PAN film

H Guo, TV Sreekumar, T Liu, M Minus, S Kumar, Polymer, 46, (2005) 3001-3005

-2

-1

0

1

2

0 20 40 60 80 100 120 140

Temperature ( 0C)

Dim

ensi

on

ch

ang

e (%

) Control PAN film

PAN/SWNT (60/40) film

CNT

PAN

molecules

8

GW Lee, S Jagannathan, HG Chae, ML Minus, S Kumar, Polymer, 49, 1831 (2008)

Drawn fiber

before heat

treatment

Fiber

after heat

treatment (170 oC)

PP

PP/CNT (1%)

Polypropylene/CNT

Near Tm, PP fiber without CNT begins to

loose orientation, while PP with CNT

retains orientation.

Shrinkage in PP/CNT was less than

20% of the shrinkage observed in PP

without CNT

9

Polypropylene/CNT - Transcrystallization Polypropylene crystallization on CNT

(a)

150m

(b)

150m

(a)

150m

(b)

150m

(b)

150m

S Zhang, ML Minus, S Kumar, LB Zhu, CP Wong, Polymer, 49, 1356-1364 (2008)

50µm

(a)

3 µm

(b)

(c)(d)

50µm

(a)

50µm

(a)

3 µm

(b)

3 µm

(b)

(c)(d)

CNT fiber

10

Interphase – Comparison between composite and nanocomposite

For creating interphase, a nano material can be 25000 times more effective than a

conventional reinforcement such as carbon fiber.

Carbon Nanotubes act as a template for polymer orientation and nucleating agent for

polymer crystallization.

Interphase

Bulk polymer

Carbon

fiber CNT

Diameter 5 µm 1 nm

Interphase

layer thickness 5 nm 5 nm

Interphase/filler

volume ratio 0.004/1 99/1

11

12

Rheology

At low shear rate, there is increased resistance to flow due to network formation

between CNTs. At high shear rate, resistance to flow decreases as CNTs and

polymer molecules align along the flow direction.

PAN/CNT

PAN

Gel spun PAN/SWNT (99/1) - HRTEM

13

Highly aligned and ordered PAN molecules

are observed in PAN/CNT fibers

HG Chae, ML Minus, S Kumar, Polymer, 47, 3494 – 3504 (2006).

Gel spun PAN/SWNT (99/1) – stabilization and carbonization

PAN PAN/SWNT (99/1)

Stabilized

Carbonized

14 HG Chae, ML Minus, A Rasheed, S Kumar, Polymer, 48(13), 3781 (2007).

Volume fraction of fibrils in the

carbonized PAN/CNT fibers is an

order of magnitude higher than

the volume fraction of SWNTs in

this fiber.

This is a result of PAN templating

on CNT

15

Carbonized gel spun PAN/SWNT (99/1) – TEM and Raman spectroscopy

PAN/CNT based carbon fibers show

well developed graphitic regions.

Graphitic regions are not observed

in PAN based carbon fibers

processed under comparable

conditions.

Presence of graphitic regions has

also been confirmed by Raman

spectroscopic studies.

PAN PAN/SWNT

HG Chae, ML Minus, A Rasheed, S Kumar, Polymer, 48(13), 3781 (2007).

Fiber spinning system

16

Fiber drawing system

Unwinding stand Drawing stands

Water rinse

stand

Drying

stand

Take-up

winder

17

Continuous carbonization line

DARPA

18

PAN and PAN/CNT precursor fibers manufactured at Georgia Tech

19

Carbon fiber processed at Georgia Tech

20

21

PEK/CNT Fibers

• Axial electrical conductivity 240 S/m

• Thermal conductivity as high as 17 W/m/K

• Density ~1.3 g/cm3

Thermally and electrically conducting polymeric fibers

R Jain, YH Choi, Y Liu, ML Minus, HG Chae, JB Baek, S Kumar, Polymer, 51, 3940-3947 (2010)

J Moon, K Weaver, B Feng, HG Chae, S Kumar, JB Baek, GP Peterson, Review of Scientific Instruments, 83, 016103 (2012)

22

0.E+0

1.E-2

2.E-2

3.E-2

4.E-2

5.E-2

6.E-2

7.E-2

0.1 1 10 100 1000

Pore Width (nm)

Incre

men

tal p

ore

vo

lum

e(c

m3/g

)

700 deg C

800 deg C

900 deg C

757 ± 23 m2/g

(BET)

1741 ± 35 m2/g

(BET)1699 ± 34 m2/g

(BET)

0

50

100

150

200

250

300

350

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Sp

ec

ific

Ca

pa

cit

an

ce

(F

/g)

Cycles

PAN/CNT (80/20)

CNT

PAN/CNT based supercapacitor electrodes

PAN/CNT based capacitors perform better

than CNT based capacitors, even after

10,000 charge/discharge cycles

S Jagannathan, T Liu, S Kumar, Composites Science and Technology, 70, 593 (2010).

Pore size control in the range of 1 to 5 nm

23

Future Directions: Functional Fibers

Using this approach functional fibers can also be made using other nano materials

– introducing corresponding functionality in the sheath or in the core. A different

nano material and hence a different functionality can be introduced in each

component. Fibers, with three or more components and hence correspondingly

more functionalities, can be made.

Lignin and cellulose nano crystals (CNCs) can be incorporated in either part of the

fiber.

A-T Chien et al., SAMPE Technical Conference Proceedings, Charleston SC, October 22-25, 2012.

Opportunities for lignin and cellulose nano crystals (CNC) for processing

structural carbon fibers, multifunctional textile fibers, and meso-porous carbon

24

Lignin/ synthetic polymer/CNT fibers

CNC/synthetic polymer fibers in combination with other nano materials

0

50

100

150

200

250

300

350

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Sp

ec

ific

Ca

pa

cit

an

ce

(F

/g)

Cycles

PAN/CNT (80/20)

CNT

Cost effective, increased functionality, and enhanced Green Foot Print

25

Contributors

• Current Group – Dr. Han Gi Chae

– Dr. Kishor Gupta

– Dr. Yaodong Liu

– Dr. Prabhakar Gulgunje

– Dr. M. G. Kamath

– Dr. Sushanta Ghoshal

– An-Ting Chien

– Brad Newcomb

– Kevin Lyons

– Ken McDonald

– Joshua Gomberg

– Andrew Gorman

– Clive Liu

– Amir Davijani

• DARPA

• AFOSR

• IPST

• ONR

• NSF

• NIST

• AFRL

• Boeing

• Rice University (Smalley, Tour)

• CNI, Unidym, CCNI

• Applied Sciences Inc

• Tao Liu – FSU

• Ioannis Chasiotis – UIUC

• Jong-Beom Baek – UNIST

• B. Feng

• G. P. “Bud” Peterson

• Art Ragauskas

• Previous group members (over 60)