Density Range of Compression-Molded Polypropylene-Wood Composites


  • Robert L. Geimer
  • Craig M. Clemons
  • James E. Wood, Jr.


Thermoplastic, fiberboard, polypropylene, density, compression molding


Wood and polypropylene fibers were mixed together in various proportions and compression-molded to boards of various specific gravities. The full theoretical specific gravity range could not be obtained even when the boards were cooled in the press. Voids surrounding the wood fibers possibly were due to the shrinkage of the wood fiber following pressing. Bending and tension properties were influenced more by the compression of the wood fibers than by the percentage of wood fiber addition.


ASTM. 1984. Standard test method for tensile properties of plastics. ASTM D638-84. American Society for Testing and Materials, Philadelphia, PA.nASTM. 1987. Standard methods of evaluating the properties of wood-base fiber and particle panel materials. ASTM D1037-87. American Society for Testing and Materials, Philadelphia, PA.nASTM. 1990. Standard test method for apparent bending modulus of plastics by means of a cantilever beam. ASTM D747-90. American Society for Testing and Materials, Philadelphia, PA.nKokta, B. V., R. G. Raj, and C. Daneault. 1989. Use of wood flour as a filler in polypropylene: Studies on mechanical properties. Polym.-Plastic Technol. Eng. 28(3):247-259.nRaj, R. G., and B. V. Kokta. 1989. Performance of polypropylene (PP)-wood fiber composites subjected to extreme conditions. Polym. Mater. Sci. Eng. 60:690-694.nVan Krevelan, D. W. 1976. Properties of polymers: Their estimation and correlation with chemical structure. Elsevier Publishing Co., New York, NY.nWoodhams, R. T., S. Law, and J. J. Balatinecz. 1990. Properties and possible applications of wood fiber-polypropylene composites. Proceedings, symposium on wood adhesives; May 16-18, 1990. Forest Products Research Society, Madison, WI.n






Research Contributions