Progress 10/01/07 to 09/30/12

Outputs
OUTPUTS: Microcrystalline cellulose (MCC)-filled engineering thermoplastic composites made from recycled nylon 6, 6 (carpet waste) were produced and evaluated via mechanical and thermal properties testing. Tensile and flexural modulus of elasticity increased with the addition of microcrystalline cellulose. Incorporation of MCC particles into recycled nylon 6, 6 also resulted in a considerable decrease of creep compliance. The thermal expansion of the composites also decreased with increased filler loading. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Cellulose derived from wood is a promising source for low cost, renewable nano-structured materials. Micro- and nanocellulose fibers exhibit low density, low damage during processing, biodegradability, low energy on processing equipment, high stiffness and a relatively low price compared to carbon nanofibers. The production of lower cost nanocomposites manufactured from cellulose to develop the next generation of light weight, high-performance, bio-based materials for a variety of defense, infrastructure and energy applications is presently a focus of world-wide research effort. Adding small amounts of cellulose-based fillers to thermoplastic matrix polymers to create nanocomposites can enhance the mechanical, thermal and barrier properties. Microcrystalline cellulose (MCC)-filled engineering thermoplastic composites (up to 30 weight percent MCC) made from recycled nylon 6, 6 (carpet waste) were produced and evaluated via mechanical and thermal properties testing. The tensile strength increased by 110% at 20 wt. % of MCC loading level. Tensile and flexural modulus of elasticity increased with the addition of microcrystalline cellulose. Incorporation of MCC particles into recycled nylon 6, 6 also resulted in a considerable decrease of creep compliance. Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) were used to determine thermal properties of the composites. The thermal expansion of the composites also decreased with increased filler loading. The mechanical and thermal properties of the composites suggest that composite components could be especially relevant in thermally challenging areas such as the manufacture of under-the-hood automotive parts.

Publications

• Peng, Y., D. J. Gardner and Y. Han. 2012. Drying cellulose nanofibrils: in search of a suitable method. Cellulose 19(1):91-102.
• Peng, Y., Y. Han, and D. J. Gardner. 2012. Spray-drying cellulose nanofibrils: effect of drying process parameters on particle morphology and size distribution. Wood and Fiber Science 44(4):448-461.
• Gardner, D. J. 2012. Cellulose nanocomposites. In: McGraw Hill Yearbook of Science & Technology. pp 28-30.
• Ozen E, Kiziltas A. Erbas Kiziltas E. and Gardner D.J. 2012. Natural Fiber Blends Filled Engineering Thermoplastic Composites for Automobile Industry. SPE Automtiive Composites Conference & Exhibition (pp. 1-12), Troy, MI: Society of Plastic Engineers.
• Kiziltas A. and Gardner D.J. 2012. Utilization of Carpet Waste as Matrix in Natural Fiber-Filled Engineering Thermoplastic Composites for Automotive Applications. SPE Automtiive Composites Conference & Exhibition (pp. 1-12), Troy, MI: Society of Plastic Engineers.
• Gardner, D. J. and Y. Han. 2012. Cellulose nanocomposites: Is the technology ready for prime time Polymer Nanocomposites 2012 Conference Processing, Properties and Applications, March 5-7, 2012, Lehigh University Bethlehem, PA
• Peng, Y., Y. Han and D. J. Gardner. 2012. Spray-drying cellulose nanofibrils: the effect of spray-drying process parameters on particle morphology and particle size distribution. 2012 Tappi International Conference on Nanotechnology for Renewable Materials, June 4-7, 2012, Montreal, PQ, Canada.
• Gardner, D. J. and Y. Han. 2012. Nanotechnology Applications in Forest Products: current trends. SWST/ICBR International Convention, August 27-31, 2012, Beijing, China
• Gardner, D. J. 2012. Nanotechnology Applications in Wood-based Materials: Past, Present and Future. 20th Anniversary Celebration of The BioEnvironmental Polymer Society (BEPS) September 18-21, 2012.

Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: Microcrystalline cellulose (MCC)-filled engineering thermoplastic composites (nylon 6 and a polyethylene terephthalate (PET)/polytrimethylene terephthalate (PTT) blend) were produced and evaluated via chemical, mechanical and thermal properties testing. Thermogravimetric analysis indicated that the MCC did not show significant initial degradation under 300 degrees C, which implies thermal stability so that MCC-filled composites could be used for high temperature circumstances, like in under the hood applications in the automobile industry. No significant chemical changes were observed in the infrared spectra of the composites. Tensile, flexural and impact tests were used to evaluate the mechanical properties of the composites as well as determining the composite densities. The composites reinforced with higher MCC filler loadings displayed enhanced tensile and flexural properties in comparison with the neat nylon 6 and PET/PTT blend. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Cellulose derived from wood is a promising source for low cost, renewable nano-structured materials. Micro- and nanocellulose fibers exhibit low density, low damage during processing, biodegradability, low energy on processing equipment, high stiffness and a relatively low price compared to carbon nanofibers. The production of lower cost nanocomposites manufactured from cellulose to develop the next generation of light weight, high-performance, bio-based materials for a variety of defense, infrastructure and energy applications is presently a focus of world-wide research effort. Adding small amounts of cellulose-based fillers to thermoplastic matrix polymers to create nanocomposites can enhance the mechanical, thermal and barrier properties. Microcrystalline cellulose (MCC)-filled engineering thermoplastic composites (nylon 6 and a polyethylene terephthalate (PET)/polytrimethylene terephthalate (PTT) blend) were produced and evaluated via chemical, mechanical and thermal properties testing. Thermogravimetric analysis indicated that the MCC did not show significant initial degradation under 300 degrees C, which implies thermal stability so that MCC-filled composites could be used for high temperature circumstances, like in under the hood applications in the automobile industry. No significant chemical changes were observed in the infrared spectra of the composites. Tensile, flexural and impact tests were used to evaluate the mechanical properties of the composites as well as determining the composite densities. The composites reinforced with higher MCC filler loadings displayed enhanced tensile and flexural properties in comparison with the neat nylon 6 and PET/PTT blend.

Publications

• Peng, Y., Y. Han, and D. J. Gardner. 2010. Cellulose nanofibrils reinforced inorganic wood composites. Society of Wood Science and Technology Annual Meeting, October 2010, Geneva, Switzerland. In: Proceedings of the International Convention of Society of Wood Science and Technology and United Nations Economic Commission for Europe Timber Committee October 11-14, 2010, Geneva, Switzerland. Paper WS-59,1-9.
• Gardner, D. J. and Y. Han. 2010. Towards Structural Wood Plastic Composites: Technical Innovations. In: Proceedings of the 6th Annual Meeting of the Nordic-Baltic Network in Wood Material Science and Engineering, October 2010, Tallinn, Estonia. pp. 7-22.
• Siddiqui, N., R. H. Mills, D. J. Gardner and D. Bousfield. 2011. Production and characterization of cellulose nanofibers from wood pulp. Journal of Adhesion Science and Technology 25:709-721.
• Kiziltas, A.,D. J. Gardner, Y. Han and H. Yang. 2011. Thermal properties of microcrystalline cellulose-filled PET-PTT blend polymer composites. Journal of Thermal Analysis and Calorimetry 103(1):163-170.
• Kiziltas, A., Y. Han, D. J. Gardner, and J. W. Nader. 2010. Development of a Carrier System for Cellulose Nanofibrils (CN) in Polymer Composites. In: Proceedings of the International Convention of Society of Wood Science and Technology and United Nations Economic Commission for Europe Timber Committee October 2010, Geneva, Switzerland Paper WS-43,1-10.
• Yang, H. S., D. J. Gardner and J. W. Nader. 2011. Dispersion evaluation of microcrystalline cellulose/ cellulose nanofibril-filled polypropylene composites using thermogravimetric analysis. Journal of Thermal Analysis and Calorimetry 103(3):1007-1015.
• Yang, H. S. and D. J. Gardner. 2011. Mechanical properties of cellulose nanofibril-filled polypropylene composites. Wood and Fiber Science 43(2):143-152.
• Yang, H. S. and D. J. Gardner. 2011. Morphological characteristics of cellulose nanofibril-filled polypropylene composites. Wood and Fiber Science 43(2):215-224.
• Kiziltas, A.,D. J. Gardner, Y. Han and H. Yang. 2011. Dynamic mechanical behavior and thermal properties of microcrystalline cellulose (MCC)-filled nylon 6 composites. Thermochimica Acta 519:38-43.

Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: The objective of the current work was to study and describe the morphologies of cellulose nanofibrils dried by different drying techniques. Different cellulose nanofibril suspensions were involved: nanofibrilated cellulose (NFC) suspension and cellulose nanocrystal (CNC) suspension. Each suspension was dried using five different drying methods to characterize the effect of drying processes on the morphologies of dried cellulose fibrils: (1) air-drying, (2) oven-drying, (3) freeze-drying, (4) critical-point drying, and (5) a novel drying method developed at the University of Maine. Scanning electron microscopy was used to examine the surface morphologies of the dried cellulose nanofbril samples. Solution characteristics including: weight percentage of fibers in suspension, suspension dilution, mixing of suspension prior to drying, and solvent characteristics have an influence on drying the cellulose nanofibrils. Different surface morphologies and particle sizes were obtained using different drying techniques with the NFC and CNC materials. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Air-drying and oven- drying was not found to be suitable for obtaining nanoscale cellulose fibrils or crystals. Critical-point drying preserved the nano-dimensions of cellulose nanofirils. Freeze-drying formed a ribbon-like material of cellulose nanofibrils.

Publications

• Kiziltas, A.,D. J. Gardner, Y. Han and H. Yang 2010. Determining the mechanical properties of microcrystalline cellulose (MCC)-filled PET-PTT blend composites. Wood and Fiber Science 42(2):165-176.
• Gardner, D. J., Y. Han, A. Kiziltas, and Y. Peng 2010. Progress on cellulose nanofiber-filled thermoplastic composites. In: Proceedings of the International Convention of SWST and UNECE Timber Committee October 11-14, 2010, Geneva, Switzerland. Paper NT-1 pp. 1-8.
• Kiziltas, A., D. J. Gardner, Y. Han, H. S. Yang, and Chris West. 2010. Structure, morphology, mechanical, and thermal properties of composites based on microcrystalline cellulose and polyamide 6. In: Proceedings of 10th International Conference on Wood & Biofiber Plastic Composites, Proceedings No. 7218-09, FPS, Madison, WI pp. 281.

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: The overall objective of this research is to investigate the influence of MCC filler loading on the mechanical and thermal properties of MCC-filled engineering thermoplastic composites. Microcrystalline cellulose (MCC) and engineering thermoplastics (nylon 6 and PET-PTT blend) were chosen as the filler/matrix combinations. Following are a summary of findings: There was not a significant change in the glass transition, crystallization and melting temperatures of the composites with increased MCC loading. The degree of crystallinity of the MCC-filled composites changed slightly after 20 percent MCC loading. The storage modulus of the MCC-filled engineering thermoplastic composite system was higher than that of the control samples and increased with increasing MCC content, this was attributed to the reinforcement effect of the MCC, and this reinforcing effect is related mainly to the cellulose network and strong interaction among cellulose particles. The tan delta peak values were not significantly changed as the MCC content increased because the viscoelastic properties of the composite are strongly influenced by the matrix polymer. Thermogravimetric analysis indicated that the onset temperature of rapid thermal degradation decreased with increasing MCC content. As the filler loading increased, the thermal stability of the composites decreased slightly. There was no statistical difference in terms of mechanical properties between the control samples and 2.5 weight percent MCC-filled composites. The composite reinforced with high filler loadings of MCC displayed enhanced tensile and flexural properties in comparison with the control samples. The results also appear to contradict to the general observations that elongation at break of the composites was greater. Izod impact strength of the composites decreased in comparison with the control samples. The density of the composites increased slightly as a function of MCC loading. This was expected since MCC has a greater density compared to the control samples. There was not a correlation between density and tensile modulus of elasticity or density and flexural modulus of elasticity. It was assumed that large improvements in the mechanical properties arose from the MCC itself. Overall, MCC-filled composites showed comparable or better mechanical properties compared to control samples without compatibilizers. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The results of this study verify that MCC can be utilized to produce engineering thermoplastic composites.

Publications

• Kiziltas A., Gardner D.J., Han Y. and Yang H. S. 2009. Determining the Mechanical Properties of Microcrystalline Cellulose (MCC) - Filled PET/PTT Blend Composites. Accepted by Wood and Fiber Science, WFS1430. This is the 3070th paper of the Maine Agricultural and Forest Experiment Station.
• Kiziltas A., Gardner D.J., Han Y. and Yang H.S. Effects of Microcrystalline Cellulose Particle Size on Mechanical, Thermal and Rheological Properties of Polystyrene Composites in the 10th International Conference on Wood & Biofiber Plastic Composites, Madison-Wisconsin USA, May 11-12 (2009).

Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Polymer composite materials were prepared from poly(ethylene terephthalate) (PET) - poly(trimethylene terephthalate) (PTT) blends as the matrix and different microcrystalline cellulose filler levels (0 to 40 weight percent) using melt compounding followed by compression molding. The composites were analyzed using dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The DSC results indicated that there was not a significant change in the glass transition (Tg) or melting temperature (Tm) of the composites with the addition of MCC. The DSC results also indicated that the crystallization temperature (Tc) decreased with increasing MCC level because of the anti nucleating effect of the MCC during the crystallization of the polymer matrix. With increasing MCC content, dynamic mechanical properties improved because of the reinforcing effect of the MCC. The tangent delta peak values from the dynamic mechanical thermal analysis were not significantly changed as the MCC content increased. Thermogravimetric analysis indicated that the initial degradation temperature decreased with increasing MCC content. It was also found that MCC-filled composites were thermally stable compared to the PET-PTT blend. No significant chemical changes were observed in the FTIR spectra of the composites. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The graduate student working on this project won first place in a graduate student poster competition at a Society of Plastics Engineering Conference on Polymer Nanocomposites at Lehigh University in March 2008

Publications

• No publications reported this period