Production of wood plastic composites from treated utility poles removed from service

The aim of this study was to investigate the dimensional stability, mechanical and biological performance, thermal degradation, leaching amount of CCA (Copper/Chrome/Arsenic) and morphology of wood-plastic composites (WPCs) made from high-density polyethylene and recycled CCA treated wood. Virgin pine wood samples were also prepared with and without a coupling agent and used as the control group. Wood-plastic composite samples of CCA-treated Scots pine (Pinus sylvestris L.) with 40, 50 and 60% wood content were produced by adding different ratios of the coupling agent. One white rot fungus, Trametes versicolor L.Pilat (Mad-697), two brown rot fungi, Postia placenta (Fr.) M.J. Larsen & Lombard (Mad-698-R) and Coniophora puteana (Schumach.: Fr.) P. Karst (Mad-15) were used for the decay tests. While Coptotermes formosanus Shiraki, a laboratory termite colony, was utilized for entomological assays. An ICP spectrometer was used as analytical instrument to determine of leaching amounts of CCA. The surfaces of the WPC samples manufactured were examined with a scanning electron microscope (SEM).The dimensional stability and mechanical performance, excluding the Izod impact, were improved by the recycled CCA wood flour and addition of the coupling agent. Produced from recycled CCA treated wood 40% and 50% with 5% MAPE flexural strength of composites gave the same values. The presence of CCA in the WPC samples resulted in degradation at lower temperatures compared to the untreated controls. However, biological resistance was higher in the CCA groups than in the control groups due to the presence of copper, chromium and arsenic in the formulations. The leaching values of As determined in the CCA samples were higher than the amount allowed for drinking water, while relatively low compared to naturally-occurring soil arsenic levels.