The compression of wood/thermoplastic fiber mats during consolidation

Abstract

Secondary processing of non-woven wood and wood/thermoplastic fiber mats is generally performed using compression molding, where heated platens or dies form the final product. Although the study and use of wood–fiber composites is widespread, few research efforts have explicitly described the fundamentals of mat consolidation. In contrast, the wood composite literature has prolifically addressed the compression of wood-strand composites. Models developed for wood-strand composites and powders are reviewed and applied to experimental data for compression of wood and wood/polypropylene (PP) fiber mats. The compression response was monitored during consolidation with varying platen temperatures, densities, and PP content. A model developed from the relationship between the instantaneous modulus and relative density was found to fit the compression of the non-woven fiber mats. The consolidation behavior was analogous to previous work with wood–fiber composites and found to be influenced by the PP content and strain rate.