Abstract:

Wood-plastic composite(WPC) is a novel material bearing excellent properties from both wood and thermoplastic. It is increasingly used in construction, furniture, decoration, transportation and interior of car. In order to reduce the cost and improve the wood texture, the wood content of commercial WPC has reached a level of 40%-60%, even greater than 70%. The high wood content causes a difficulty in extrusion processing of WPC, where the flow of melt is unstable and the surface of extruded WPC exhibits a tear phenomena. In addition, the quality of WPC and the processing efficiency also decrease. Up date, the rheological behavior of highly filled WPC melt is still not fully understood due to lacking of the systematic theoretical basis. When plastic matrix is filled with high content of wood fiber, the interactions of fiber-fiber and fiber-polymer will enhance. In this complex system, dominant factors of rheological behavior include the lignocellulosic material (species, particle size, and content), the molecular structure of the polymer matrix (molecular weight and molecular weight distribution), lubricants, and coupling agents. In this paper we reviewed the previous studies aiming at providing a theoretical and scientific foundation for proper formula design, process control, processing equipment upgrade, and die manufacture of WPC.

Key words: lignocellulosic material, wood-plastic composite, thermoplastic, rheological behavior, extrusion