Sustainable biocomposites produced from cotton stalk wastes: Effect of heat treatment

The novelty of this study is to explore the effect of heat treatment of CS on the properties of biocomposites. 200°C, 300°C, 500°C, and burning of 500°C were selected to heat treat CS to obtain CS fillers, and the biocomposites were prepared using CS fillers and LLDPE. The heat treatment of CS can improve the interface bonding and compatibility of biocomposites by the results of FTIR, SEM, and CA. The crystal planes were not changed by the addition of CS fillers. The results of DSC and TGA showed that the heat treatment of CS promoted crystallization and improved the heat resistance of LLDPE. In addition, the flexural properties, tensile properties, stiffness, elasticity, creep resistance, and stress relaxation resistance were all increased by the heat treatment of CS, although it exhibited an adverse effect on the impact strength of LLDPE. After comparison, the best flexural strength and modulus (13.00 MPa and 0.75 GPa) were obtained in 200CSB-L due to the enhancement of CS rigidity by 200°C heat treatment. Also, 200CSB-L showed the best stiffness, elasticity, and dimensional stability than others. The best tensile strength and modulus (10.89 MPa and 0.26 GPa) were obtained in 500CSB-L due to its mechanical interlocking structure. The results of this study indicate that heat treatment would play an important role in biocomposites in terms of the benefit in mechanical properties.