Jonathan G. Phillips

Elasticity of wood and wood polymer composites in tension compression and bending

SummaryThe ratio of tensile to compressive modulus of elasticity for untreated basswood was approx. 1.9 and for untreated sugar maple approx. 1.3. It approached 1.1 with high polymer loadings. The method of transformed sections gave good estimates of along the grain, tensile, compressive and bending elastic values for maple wood and maple wood polymer composite.

Static bending and toughness of wood polymer composites (yellow birch and basswood)

Wood polymer composites (WPC) were made from basswood and yellow birch using six cell lumen type polymer formulations. The study was designed to get insight into the influence of wood density and polymer formulation on certain WPC mechanical properties. Small specimens were tested for toughness, stiffness, hardness and bending strength using standard ASTM methods. Results showed that stronger and stiffer polymers produce tougher and stronger WPC, but the effect is small. Thus, there is a wide range of polymer properties which produce useful WPC properties. Study of the fracture surfaces using Scanning Electron Microscopy (SEM) showed that WPC made with different polymers fractured differently and polymer containing a coupling agent bonded to the cell wall. However the cell wall bonding had no noticeable influence on WPC mechanical properties.