The rheology and extrusion processing performance of wood/melamine composites

A modified melamine resin that exhibits both thermoplastic and thermoset behaviors was used as a matrix for wood plastic composites (WPCs). The thermoplastic melamine (TPM) resin exhibits a glass transition at approximately 34°C and continues to be thermally malleable until a crosslinking reaction develops with additional heating and an acid catalyst. Varying blends of TPM and wood flour were evaluated for their rheology and curing behavior using torque rheometry. WPC composites were manufactured with extrusion methods and final product properties determined. The torque rheometry results showed a highly dependent relationship of the curing behavior to the amount of wood flour utilized and temperature. Based upon the torque rheometry results, two extrusion platforms were developed to initiate the curing process; (1) cure within the die land and (2) post‐cure of the extrudate. The post‐cure procedure provided composites with higher mechanical properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39858.