Effects of thermal treatment and maleic anhydride-grafted polyethylene on the interfacial shear stress between cotton stalk and high-density polyethylene

For investigating the interfacial bonding between natural fiber and polymer matrix, modified ASTM D905 was used to test the interfacial shear stress between cotton stalk and high-density polyethylene (HDPE). The effects of thermal treatment and maleic anhydride-grafted polyethylene(MAPE) content on interfacial shear stress were investigated. Thermogravimetry analyze (TGA) and Fourier Transform Infrared Spectroscopy (FTIR) was employed to evaluate thermal treatment of cotton stalks. TGA and FTIR results indicate that more amount of fiber degrade at higher treatment temperature. Interfacial shear stress increases with increasing MAPE content, and decreases with increasing temperature of thermal treatment. Fiber failure at surface of tested HDPE matrix increased with thermal treatment temperature and MAPE content. Thermal treatment weakened the strength of cotton stalk, but improved wettability between cotton stalk and HDPE. MAPE improved the interfacial shear stress through chemical bonding and mechanical interlocking. Interfacial shear stress was affected by both the fiber strength and interface wettability.