BIO-BASED NANOCOMPOSITES: CHALLENGES AND OPPORTUNITIES. John Simonsen Department of Wood Science & Engineering Oregon State University

Transcription

1 BIO-BASED NANOCOMPOSITES: CHALLENGES AND OPPORTUNITIES John Simonsen Department of Wood Science & Engineering Oregon State University

2 Outline What is the difference between composites and nanocomposites? Nanocrystalline cellulose (NCC, CNXL) Experimental results Polyhydroxyoctanoate PVOH PUR Polysulfone (PSf) CMC Challenges and opportunities Acknowledgements

3 Polymer Composites Generally consists of a polymer matrix and a particulate filler Filler (dispersed phase) is dispersed in matrix (continuous phase) Can also have continuous filler (graphite fiber pultrusion, used for aerospace, etc.), but not yet used in nanocomposites

4 Wood flour in HDPE 0.1 mm

5 Synergism in Polymer Composites Function of matrix: Disperse fibers Transfer load to filler Load sharing between broken and intact filler particles Increases toughness Function of filler Carry load, increase properties Lower cost

6 What makes a nanocomposite different?

7 Reduced impurities As the size of a particle is reduced, the number of defects per particle is also reduced Mechanical properties rise proportionately

8 Properties of fibers and nanoparticles material Density, Theoretical g/cm3 strength, GPa ρ Whisker Bulk strength (S), strength, GPa GPa Specific whisker strength S/ ρ iron Carbon 1.38 (graphite)

9 An historical nano-example: Carbon black

10 2004_06_15_carbon_black.Par.0006.posterImage.jpg

11 2004_06_15_carbon_black.Par.0006.posterImage.jpg

12 Addition of nano-sized carbon to rubber Particle size nm Strength can increase 1000 X Stiffness increases 7 X (in accordance with modified Einstein equation) Abrasion resistance 4-5 X Without carbon black, tires would not be made from rubber!

13 Surface Area E-glass fibers* Paper fibers Graphite Fumed silica Fully exfoliated clay Cellulose nanocrystals** Carbon nanotubes*** m2/g ~ ~ ~ 100 * ** Winter, W. presentation at ACS meeting, San Diego, March 2005 ***

14 Polymer-clay nanocomposites mechanical and barrier properties

15 The step-assist on the 2002 GMC Safari (shown) and Chevrolet Astro vans is the automotive industry's first exterior applications for thermoplastic polyolefin-based nanocomposites. The part won General Motors the 2001 Grand Award for plastics innovation from the SPE's Automotive Division. (Photo courtesy of Wieck Photo Database).

16 Nano-PA6 Using Nanomer 1.24 TL - In Situ Polymerization

17 Aspect ratio > 100 intercalation Confined polymer exfoliation U. Southern Miss. Macrogalleria

18 Barrier Platform Mitsubishi gas chemical and Nanocor Alliance Imperm Nano-Nylon MXD6

19 Barrier Film for packaging Nano-PA6 using Nanomer 1.24 TL - In situ polymerization

20 Percolation Relative electrical conductivity ( c/ m) of the carbon black filled LDPE (circles) or HDPE (squares) as a function of the filler content ( ). I. Chodak, I Krupa. J. Mat. Sci. Lttrs :

21 Percolation threshold ~ 1% Aspect ratio = 50 Garboczi, et. al. Phys. Rev. Ltrs. E, 1995, 52(1):

22 Nanocomposite Concepts Reduced defects Surface area Percolation Interphase volume Polymer morphology

23 Cellulose

24 Cellulose Nanocrystal (CNXL) Production Amorphous region Native cellulose Crystalline regions Acid hydrolysis Individual nanocrystals Individual cellulose polymer

25 Sources of nanocrystalline cellulose Microcrystalline cellulose (wood) Bacteria (Nata de coco) Cotton Ag wastes Tunicates

26 Cellulose nanocrystals Cellulose source Length Cross section Tunicate 100 nm microns nm Algal (Valonia) Bacterial Cotton Wood Aspect ratio 5 to > 100 (high) > 1000 nm 10 to 20 nm 50 to > 10 nm (high) 100 nm 5-10 x to > 100 microns nm (medium) nm 5 nm 20 to 70 (low) nm 3 5 nm 20 to 50 (low) Beck-Candanedo, et. al. Biomacromol. (2005) 6:

27 COST OF CELLULOSE NANOCRYSTALS Microcrystalline cellulose (MCC) ~ $7/kg HCl based process Nanocrystalline Cellulose (CNXL) Target ~ $2/kg H2SO4 based process Do you need the purity of MCC starting material? Can acid be recovered? Uses for byproduct (sugar in acid)?

28 TEM image of cellulose nanocrystals

29 Polymer systems

30 Battery Separator, CNXL in Polyhydroxyoctanoate Fuel cell operating temp M. Samir, F. Alloin, J-Y Sanchez, A. Dufresne, Macromol. 37:

31 BACTERIAL CELLULOSE/ POLYVINYLALCOHOL

32 Slide from Wankei Wan, U. W. Ontario, London, ON, Canada

33 x Slide from Wankei Wan, U. W. Ontario, London, ON, Canada

34 Slide from Wankei Wan, U. W. Ontario, London, ON, Canada

35 Slide from Wankei Wan, U. W. Ontario, London, ON, Canada

36 Slide from Wankei Wan, U. W. Ontario, London, ON, Canada

37 Cellulose nanocrystal-filled polyurethane

38 Slide from Mirta Aranguren, UNMdP-CONICET, Buenos Aires, Argentina

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40 Polysulfone/cellulose nanocomposites Sweda Noorani John Simonsen

41 TGA-16% NCC Sample: sample2_dec 30_tga Size: mg Method: Ramp TGA File: C:\Data\sweda\sample2_dec30_tga.001 Operator: sweda Run Date: 30-Dec-04 12:02 Instrument: 2950 TGA HR V6.0E % (0.2281mg) Weight (%) % (0.7699mg) Temperature ( C) Universal V3.3B TA Instruments

42 Sample: sample1_dec 30_tga Size: mg Method: Ramp TGA-11% NCC File: C:\Data\sweda\sample1_dec30_tga.001 Operator: sweda Run Date: 30-Dec-04 10:41 Instrument: 2950 TGA HR V6.0E TGA % (0.1496mg) Weight (%) % (0.9396mg) Temperature ( C) Universal V3.3B TA Instruments

43 TGA (Psf film with 2% NCC) Sample: psf film (ncc)nov 17, 04 Size: mg Method: Ramp TGA File: C:...\sweda\psf film(ncc) nov 17, Operator: sweda Run Date: 17-Nov-04 17:07 Instrument: 2950 TGA HR V6.0E 120 Weight (%) % (1.024mg) Temperature ( C) Universal V3.3B TA Instruments

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49 20x70 nm

50 CELLULOSE NANOCRYSTAL-FILLED CARBOXYMETHYL CELLULOSE YongJae Choi

51 Comparison of Microcrystalline Cellulose (MCC) to NCC in CMC 10% MCC 10% NCC 10% glycerin plasticizer 200X optical (crossed polars)

52 CROSS SECTION OF FILM 90%CMC/10%Gly 80%CMC/10%NCC/10%Gly

53 Tensile strength (MPa) Mechanical properties (MOR) Control 40 NCC 30% increase MCC % NCC/MCC content 25 35

54 Mechanical properties (MOE) 3 NCC 2.6 MCC 2.4 MOE (GPa) 85% increase Control % NCC/M CC content

55 Extension at failure % increase Extension (mm) control NCC MCC %NCC or %MCC, wt/wt 25 35

56 HEAT TREATMENT 5% NCC in CMC (H form) No plasticizer

57 HEAT TREATMENT 6 Tensile strength, MPa 92 16% increase MOR 80 MOE 78 Elongation Heat treatment, C for 3 h, 5% NCC-filled CMC MOE, GPa or % elongation 94

58 Water Dissolution 60 Weight loss (%) C 100C 30 80C No heat Water immersion Time (hr) 55 75

59 Water vapor transmission rate % reduction WVTR, g/m2 dy control heat treated

60 CHALLENGES Dispersion of nanoparticles Production scale-up of nanoparticles Coupling of filler to matrix Where are the high stiffness, high strength composites we should have? Improving knowledge base to allow intelligent design of products which capture the advantages of this exceptional nanomaterial

61 OPPORTUNITIES - APPLICATIONS Membranes Fuel cells Kidney dialysis Reverse osmosis Protein separation Pervaporation

62 APPLICATIONS Advanced textiles fibers Again, where are the high stiffness, high strength composites we should have? Biomedical Tissue engineering Heart valves bone replacement materials

63 APPLICATIONS Advantages Biocompatible Biodegradable Exceptional mechanical properties Chemical modification straightforward Self-assembling?

64 Acknowledgements This project was supported by a grant from the USDA National Research Initiative Competitive Grants Program

65 QUESTIONS?

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