Study On The Static Viscoelasticity Of Wood-plastic Composites

Wood-plastic composites (WPC) is a new kind of environment-friendly materials whichcombined with the double advantages of wood and plastic. To make WPC a better use instructural application, it’s urgent to study the vicoelasticity of WPC deeply and systematically.In this paper, we will investigate the static viscoelasticity of self-prepared5kind WPC withdifferent wood-plastic ratio by DMA under5different temperatures, fit the creep compliance andstress relaxation modulus curves with viscoelastic models, predict the long term creep and stressrelaxation properties of WPC with TTSP. The results are:(1) Beside time, the creep behavior of WPC is also with high relation of temperature andwood-plastic ratio. The creep compliance of WPC increase dramatically with the rise oftemperature. There is no significant influence on30min creep compliance of WPC whenwood-plastic ratio changes in this research under low temperature, while the temperature raises,the WPC with low wood-plastic ratio showes high creep compliance. The creep compliance ofthese kinds of WPC is higher than Chinese fir, there is little influence of temperature on thecreep compliance of Chinese fir in the range of this paper.Both Burgers model and findleyPower Law have a good fitting with creep compliance curves, the coefficient of determinationare all above0.99.TTSP underestimate the long term creep behavior of these kinds of WPC.(2) The stress relaxation modulus of WPC is with high relation of time, and is also deeplyinfluenced by temperature and wood-plastic ratio.The stress relaxation modulus of WPCdecreases with the raises of temperature. The30min final stress relaxation modulus increaseswith the increase of wood-plastic ratio under low temperature, while no significant influenceunder high temperature. The stress relaxation modulus of these kind of WPC is lower thanChinese fir, there is little influence of temperature on the stress relaxation modulus of Chinese firin the range of this paper. Both Zener model and logarithmic model have a good fitting withstress relaxation modulus curves. TTSP predict the long term stress relaxation behavior well ofthese kinds of WPC.