Measurements of stress relaxation of two samples of decking boards after exposure in rain and chlorinated water, in ice, and in a mixture of gasoline and water in different concentrations from 1 to 7% were carried out. Samples consisting of 60% wood flour, 30% polyvinyl chloride and 10% additives were used for measurements. Additives are flame retardants, stabilizers, modifiers and dyes. The mineral filler CaCO3 was used as modifier. In sample No.1, the CaCO3 content was 42% and the wood content was 18%. For sample No.2, the CaCO3 content was 24% and the wood content was 36%. As a result of measurements after exposure for 200 days, it was found that the relative drop in mechanical stress decreases when the mineral filler is added to the composition. The nonlinear mechanical behavior for the initial sample No.1 is observed at 2% strain, and for the sample No.2 – at 3% strain. When aged in chlorinated water and in ice, the nonlinear mechanical behavior is observed for all deformations. The generalized relaxation curves indicate that decking boards can be used with confidence for a long time.
Influence of aggressive media on the relaxation properties of wood-polymer composites
