Effect of Surface Free Energy of Wood-flour and Its Polar Component on the Mechanical and Physical Properties of Wood-Thermoplastic Composites
The interface between wood fibers and plastic strongly influences the mechanical and physical properties of a wood-fiber/plastic composite, and the properties of wood-flour affect the interface. The primary objectives of this study were to investigate the relationship between surface free energy of wood-flour and the mechanical and physical properties of wood-polyethylene composites (WPCs). The contact angles of different liquids against poplar wood-flour were measured with capillary rise methods before and after the modification with n-stearylacrylate, the surface free energy and the correspondent dispersive and polar components were calculated based on Washburn equation and the methodology suggested by Owens-wendt-Kaelble, the tensile strength, flexural strength and of the WPC samples extruded with the unmodified and modified WF (the ratio of wood-flour to high-density polyethylene(HDPE) is 70:30) were tested and the fracture surface of the WPC samples were analyzed with scanning electron microscopy (SEM), the effects of surface treatment on the water absorption and thickness swelling were studied as well. The results showed that the surface free energy of WF increased from 23.43mJ/m2 to 46.88 mJ/m2, which was higher than the surface free energy of HDPE (31.2 mJ/m2), and its correspondent polar component decreased from 18.79 mJ/m2 to 1.21 mJ/m2 and the dispersive component increased from 4.64 mJ/m2 to 45.67 mJ/m2 after the modification with 4% of n-stearylacrylate, which make it ready for the spreading of HDPE on the surface of WF. The tensile strength and flexural strength were obviously improved due to the modification. The water absorption and thickness swelling of WPC samples prepared with the modified WF were lower than those with the unmodified WF which could be attributed to the poor adhesion between the unmodified WF and polymer matrix. The improved compatibility between WF and HDPE was well confirmed by SEM.
Yong-Ming Fan Chao-Qun Mei Yang Liu Lei Mei
College of Material Science and Technology, Beijing Forestry University, Beijing 100083, China College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
国际会议
桂林
英文
1-9
2010-11-16（万方平台首次上网日期，不代表论文的发表时间）