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Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
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Title: Characterizing Macroscopic Creep Behavior of Wood-Plastic Composites in Tension and Compression

Source: IN: 10th International Conference on Wood & Biofiber Plastic Composites and Cellulose Nanocomposites Symposium : May 11-13, 2009, Monona Terrace Community & Convention Center, Madison, Wisconsin, USA. Madison, WI : Forest Products Society, c2010. 289 p. ISBN: 9781892529558; 2010

Author(s)Hamel, S.E.; Bechle, N.J.; Hermanson, J.C.; Cramer, S.M.

Publication Year: 2010  View PDF »

Category: Conference Proceedings
Associated Research Project(s):   FPL-4714-2A

Abstract: The polymers within wood-plastic composites (WPCs) are known to experience significant time-dependent deformation, or creep. While extensive work has been done on the creep behavior of pure polymers, little information is available on the effects of mixing the polymers with large amounts of wood or other bio-based fillers. As the market increases for structural WPC products that may be subjected to sustained loads, it is imperative that this creep behavior be understood. This study characterizes the time-dependent deformation of two WPC formulations [polypropylene and high-density polyethylene (HDPE)] in tension, compression, and flexure. It was found that the power law (Findley, Shapery, etc.) fits the data at various stress levels and loading mechanisms, for both formulations. This means that the deformation rate linearly decreases in log-log space and, after 400 d of testing; almost all the tests that have not failed remain in primary creep. The time-dependent constants associated with the power law and their stress dependencies are also presented.

Keywords: Polyethylene; composite materials; deterioration; thermoplastic composites; mechanical properties; deformations; creep; extrusion process; injection molding of plastics; wood-plastic composites; modulus of elasticity; thermoplastic composites; bending; polypropylene; wood-plastic materials; HDPE; failure; tension; strength; tensile strength; bending strength; compression tests; high density polyethylene; power law

Publication Review Process: Non-Refereed (Other)

File size: 263 kb(s)

Date posted: 06/06/2011
RITS Product ID: 36106
Current FPL Scientist associated with this product
Hermanson, John C.
Research General Engineer

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