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

Transcription

1 BIO-BASED 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, g/cm 3 ρ Theoretical strength, GPa Whisker strength (S), GPa Bulk strength, GPa Specific whisker strength S/ ρ iron Carbon (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 X Without carbon black, tires would not be made from rubber!

13 Surface Area m 2 /g E-glass fibers * ~1 Paper fibers 4 Graphite Fumed silica Fully exfoliated clay ~ 500 Cellulose nanocrystals 250 Carbon nanotubes*** ~ 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 Nylon MXD6

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

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

21 Percolation threshold ~ 1% Aspect ratio = 70 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 Native cellulose Amorphous region 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 source Tunicate Algal (Valonia) Bacterial Cellulose nanocrystals Length 100 nm microns Cross section Aspect ratio nm 5 to > 100 (high) > 1000 nm 10 to 20 nm 50 to > 10 nm (high) 100 nm microns Cotton nm 5 nm 5-10 x nm Wood nm 3 5 nm Beck-Candanedo, et. al. Biomacromol. (2005) 6: to > 100 (medium) 20 to 70 (low) 20 to 50 (low)

27 COST OF CELLULOSE NANOCRYSTALS Microcrystalline cellulose (MCC) ~ $7/kg HCl based process Nanocrystalline Cellulose (CNXL) Target ~ $10/kg H 2 SO 4 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 Slide from Wankei Wan, U. W. Ontario, London, ON, Canada x

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 Sample: sample2_dec 30_tga Size: mg Method: Ramp 100 TGA-16% CNXL TGA File: C:\Data\sweda\sample2_dec30_tga.001 Operator: sweda Run Date: 30-Dec-04 12:02 Instrument: 2950 TGA HR V6.0E 11.52% (0.2281mg) 80 Weight (%) 38.88% (0.7699mg) Temperature ( C) Universal V3.3B TA Instruments

42 Sample: sample1_dec 30_tga Size: mg Method: Ramp 120 TGA-11% CNXL TGA File: C:\Data\sweda\sample1_dec30_tga.001 Operator: sweda Run Date: 30-Dec-04 10:41 Instrument: 2950 TGA HR V6.0E % (0.1496mg) Weight (%) % (0.9396mg) Temperature ( C) Universal V3.3B TA Instruments

43 Sample: psf film (ncc)nov 17, 04 Size: mg Method: Ramp 120 TGA (Psf film with 2% CC) TGA File: C:...\sweda\psf film(ncc) nov 17, Operator: sweda Run Date: 17-Nov-04 17:07 Instrument: 2950 TGA HR V6.0E 100 Weight (%) % (1.024mg) Temperature ( C) Universal V3.3B TA Instruments

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49 20x70 nm

50 Nanocrystalline cellulose in PSf MOE (GPa) % NCC (w/w)

51 WVTR of CNXL-filled PSf Flux (g/m 2 dy) %NCC

52 CELLULOSE NANOCRYSTAL-FILLED CARBOXYMETHYL CELLULOSE YongJae Choi John Simonsen

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

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

55 Mechanical properties Tensile Strength (MPa) % increase Control CNXL MCC CNXL or MCC content ( % w/w)

56 Mechanical properties Tensile modulus (GPa) % increase Control CNXL MCC CNXL or MCC content (% w/w)

57 Extension at failure 7 60% increase 6 Elongation (%) control CNXL MCC CNXL or MCC content (% w/w)

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

59 HEAT TREATMENT Tensile strength, MPa % increase MOR MOE MOE, GPa or % elongation 78 Elongation Heat treatment, 0 C for 3 h, 5% NCC-filled CMC

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

61 Water vapor transmission rate % reduction WVTR, g/m 2 dy control heat treated

62 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

63 OPPORTUNITIES - APPLICATIONS Membranes Fuel cells Kidney dialysis Reverse osmosis Protein separation Pervaporation Barrier films

64 APPLICATIONS Advanced textiles fibers If properties of CNXLs can be accessed efficiently Biomedical Tissue engineering Heart valves bone replacement materials Skin grafts

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

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

67 QUESTIONS?

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