Improvement of the weathering resistance of wood /polyethylene composite using carbamate derivatives (IPBC) and Thiabendazole preservative materials

Poplar wood flour was spray treated with two preservative materials, (Thiabendazole or Carbamate derivatives (IPBC) with concentration of 0.9%) and then the wood/polyethylene composite samples with the composition of 60% wood, 38% polyethylene and 2% coupling agent were manufactured. The treated composite and control samples were exposed to weathering for 5 months using ASTM D1435 standard test method and the structural changes of the samples were analyzed using SEM microscopy. The roughness of WPCs was measured by roughness measuring device (Miyutoyo SJ 201P) before and after weathering. The SEM images showed that the highest surface changes due to weathering occurred in untreated samples. Both preservatives improved the weathering resistance of treated WPC. The differences in the roughness values root mean square roughness (Rq), mean peak-to-valley height (Rz) and average roughness (Ra)  before and after weathering were measured as 7.93, 38 and 4.88µm for control samples, 1.65, 21.7 and 42.2 µm for Thiabendazole-treated and 1.2, 1.5 and 0.79 µm for IPBC-treated samples, respectively. Both preservative materials significantly improved the weathering resistance of WPCs.