Experimental and modeling studies on water absorption kinetics of recycled wood-polymer composites

摘要

The water absorption and diffusion properties of wood flour/polymer composites were studied according to the different compositions. We have chosen to work with similar particle size either for the wood flour or for the chosen polymer. Diffusion and absorption of moisture in virgin (WPCv) or recycled (WPCr) composites were carried out at different immersion times in water at ambient temperature. Also, the measurements of absorption, swelling and diffusion coefficients were carried out for all WPC composites at different wood flour contents. The results showed that the response of WPCr to water immersion strongly depends on the content of wood powder. Any increase in wood content leads to an increase in water uptake. CaCO 3 additives reduce swelling and water absorption. WPCv expressed higher swelling and water absorption values than WPCr. The highest diffusion coefficients were detected in the composites with a high wood content. The study of water absorption in WPCs has clearly indicated that the process follows kinetics and mechanisms described by Fick's law. The understanding of water-polymeric composites interactions is achieved through the measurements of static water contact angles on the surfaces of the WPCr by indicating the hydrophobicity of the polymer and hydrophilicity of the wood.