Dynamic Viscoelasticity of Wood-Polymer Composites Prepared by an Electron Beam Accelerator
The dual characteristics in the performance of polymers in wood systems have been pursued with regard to the resolution of mechanical anisotropy of wood and the improvement in dimensional stability. The increase of the dynamic modulus in the tangential direction of wood (EL’) vs. polymer converged ideally to EL’ in the. longitudinal direction of wood at a polymer fraction of 1.0. This increase of ET’ is due to the interaction between polymer and the surface of the cellular parts, as illustrated by the rise of the loss modulus (ET”)-peak ranging from 100°C to 150°C. As for the performance of polymer grafted to the cellular parts, stabilization of wood to moisture was found by noting the decrease of dielectric loss peak at low temperatures (corresponding to the rotational motion of methylol groups of the amorphous cellulose and hemicellulose). As a result, it seems likely that the performance of polymers in wood to strengthen its properties is deeply concerned with the balance between the mechanical gain (increase in ET’ and ET” of wood) and the improvement in its dimensional stability to reduce the shear by swelling on the kind of polymerization specific to the individual polymers, their molecular structure, their residential sites, and their content in wood.
KeywordsLoss Modulus Dimensional Stability Dynamic Modulus Polymer Content Amorphous Cellulose
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