Carbon Fibers, Multi-functional Textile Fibers, Meso-porous Carbon

Transcription

1 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 Institute of Paper Science and Technology April 18,

2 Carbon Fibers 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, (2005) 2

3 Lignin based Carbon Fibers 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. 3

4 Fiber and Carbon Fiber Processing Facilities at Georgia Tech 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 cleanroom. Continuous carbonization of 100 to 6000 filaments has been demonstrated on this line. Well equipped fiber characterization and testing facility. 4

5 Stress (GPa) N O N O n PBO PBO/SWNT(90/10) 3.5 SWNT PBO Strain (%) 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). 5

6 D* band peak position (cm -1) Absorbance (a. u) 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. UV-VIS Spectra Stress-strain curves d c b a Raman D* band shift with strain Wavelength (nm) (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%) Raman D* band shift with strain Strain (%) XF Zhang, T Liu, TV Sreekumar, S Kumar, VC Moore, RH Hauge, RE Smalley, Nano Lett, 3(9), 1285 (2003). 6

7 PAN/CNT early developments At 10% CNT, 50 times increase in modulus at 140 o C, and 40 o C increase in Tg Individual CNT in PAN matrix 5 nm TV Sreekumar, T Liu, BG Min, H Guo, S Kumar, RH Hauge, RE Smalley, Advanced Materials, 16(1), 58 (2004). 7

8 Dimension change (%) tanδ PAN/SWNT (60/40) Film Electrical conductivity (~10 4 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/ o C) Polymer molecular motion above glass transition temperature is dramatically suppressed. Low density (~1 g/cm 3 ) Thermally stable and exhibits Chemical resistance PAN molecules CNT Control PAN film Control PAN film 0 PAN/SWNT (60/40) film Temperature ( 0 C) PAN/SWNT (60/40) film Temperature ( o C) H Guo, TV Sreekumar, T Liu, M Minus, S Kumar, Polymer, 46, (2005)

9 Polypropylene/CNT Drawn fiber before heat treatment Fiber after heat treatment (170 o C) Shrinkage in PP/CNT was less than 20% of the shrinkage observed in PP without CNT PP PP/CNT (1%) Near Tm, PP fiber without CNT begins to loose orientation, while PP with CNT retains orientation. GW Lee, S Jagannathan, HG Chae, ML Minus, S Kumar, Polymer, 49, 1831 (2008) 9

10 Polypropylene/CNT - Transcrystallization Polypropylene crystallization on CNT (a) CNT fiber (b) (a) (c) 50µm (d) 3 µm (b) 150 m 150 m S Zhang, ML Minus, S Kumar, LB Zhu, CP Wong, Polymer, 49, (2008) 10

11 Interphase Comparison between composite and nanocomposite Carbon fiber CNT Diameter 5 µm 1 nm Interphase layer thickness Interphase/filler volume ratio 5 nm 5 nm 0.004/1 99/1 Interphase Bulk polymer For creating interphase, a nano material can be 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. 11

12 Rheology PAN/CNT PAN 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. 12

13 Gel spun PAN/SWNT (99/1) - HRTEM Highly aligned and ordered PAN molecules are observed in PAN/CNT fibers HG Chae, ML Minus, S Kumar, Polymer, 47, (2006). 13

14 Gel spun PAN/SWNT (99/1) stabilization and carbonization Stabilized PAN PAN/SWNT (99/1) Carbonized 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 HG Chae, ML Minus, A Rasheed, S Kumar, Polymer, 48(13), 3781 (2007). 14

15 Carbonized gel spun PAN/SWNT (99/1) TEM and Raman spectroscopy PAN PAN/SWNT 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. HG Chae, ML Minus, A Rasheed, S Kumar, Polymer, 48(13), 3781 (2007). 15

16 Fiber spinning system 16

17 Fiber drawing system Unwinding stand Drawing stands Water rinse stand Drying stand Take-up winder 17

18 Continuous carbonization line 18 DARPA

19 PAN and PAN/CNT precursor fibers manufactured at Georgia Tech 19

20 Carbon fiber processed at Georgia Tech 20

21 Thermally and electrically conducting polymeric fibers PEK/CNT Fibers Axial electrical conductivity 240 S/m Thermal conductivity as high as 17 W/m/K Density ~1.3 g/cm 3 R Jain, YH Choi, Y Liu, ML Minus, HG Chae, JB Baek, S Kumar, Polymer, 51, (2010) J Moon, K Weaver, B Feng, HG Chae, S Kumar, JB Baek, GP Peterson, Review of Scientific Instruments, 83, (2012) 21

22 Specific Capacitance (F/g) Incremental pore volume(cm 3 /g) PAN/CNT based supercapacitor electrodes 7.E-2 Pore size control in the range of 1 to 5 nm 6.E-2 5.E-2 4.E-2 3.E ± 35 m 2 /g (BET) 1699 ± 34 m 2 /g (BET) 700 deg C 800 deg C 900 deg C 2.E-2 1.E ± 23 m 2 /g (BET) PAN/CNT (80/20) CNT 0.E Pore Width (nm) PAN/CNT based capacitors perform better than CNT based capacitors, even after 10,000 charge/discharge cycles Cycles S Jagannathan, T Liu, S Kumar, Composites Science and Technology, 70, 593 (2010). 22

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,

24 Specific Capacitance (F/g) Opportunities for lignin and cellulose nano crystals (CNC) for processing structural carbon fibers, multifunctional textile fibers, and meso-porous carbon Lignin/ synthetic polymer/cnt fibers CNC/synthetic polymer fibers in combination with other nano materials PAN/CNT (80/20) CNT Cycles Cost effective, increased functionality, and enhanced Green Foot Print 24

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) 25