Effects of Tobacco Stalk Powder and Coffee Shell Powder on Properties of Wood-plastic Composites

In order to explore the feasibility of tobacco stalk powder and coffee shell powder instead of eucalyptus wood powder in the production of wood-plastic composites(WPC), the chemical compositions of tobacco stalk powder, coffee shell powder and eucalyptus wood powder were analyzed and compared by the method of Van Soest. The tobacco stalk powder, coffee shell powder and eucalyptus wood powder were used as reinforcement phases, and HDPE was used as matrix. WPC with different lignocellulosic materials and ratios were prepared by two-step extrusion molding method. By testing the physical and mechanical properties, DMA, OIT and OIT* of WPC, and observing the micromorphology and functional groups of WPC, the effects of different lignocellulosic materials and their ratios on the properties of WPC were analyzed. The results showed that the contents of polycellulose from high to low were eucalyptus wood powder, tobacco stalk powder and coffee shell powder, while the contents of lignin from low to high were eucalyptus wood powder, tobacco stem powder and coffee shell powder. The comprehensive performance of eucalyptus powder/HDPE composite(TS0) was better than that of tobacco stalk powder/HDPE composite(TS100) and coffee shell powder/HDPE composite(CS100). The elastic modulus, static flexural strength, concentrated load, and impact strength of WPC increased first and then decreased with the decrease of eucalyptus powder content, and the OIT and OIT* decreased. The comprehensive performance of 20% tobacco stalk powder and 80% eucalyptus powder/HDPE composite(TS20) was the best. Compared with the TS100, the concentrated load and impact strength of the composite were increased by 27.5% and 22.5%, respectively, and the OIT and OIT* were increased by 9.9 min and 10.7 ℃, respectively.