Stress relaxation of wood-polymer composites of savewood

Experiments on stress relaxation on the samples representing fragments of terraced boards have been carried out. Matrix polymer is polyvinyl chloride (PVC). The combined wood filler, which is a mixture of wood flour and chalk, has been used. Measurements conducted at different permanent deformations of compression from 2 to 5% and temperatures from 20 to 70°C. Found that under all conditions the relative relaxation takes small values, indicating the long-term conservation of the mechanical workability of the products. Nonlinear mechanical behavior is evident already at 3% strain. At temperatures from 20 to 35°C relaxation processes take place almost identically, without reduction in initial and final stress. At temperatures of 50 and 70°C both stresses are reduced. The master curve is plotted, which allows prediction the mechanical behavior for a long time