Material ratio and properties of polylactic acid/polypropylene carbonate/corn stover composites.

Abstract

Polylactic acid (PLA)/corn stover composites exhibit the drawback of high brittleness, while polypropylene carbonate (PPC) possesses excellent flexibility. Therefore, this study employed PPC to enhance and toughen PLA/corn straw composites. Using the response surface methodology, the preparation process and formulation of PLA/PPC/corn straw composites were thoroughly investigated and optimized. Through multi-objective analysis of regression equations, the optimal material parameters were determined as follows: PLA:PPC ratio of 54:46, corn straw content of 62 %, and corn straw particle size of 80-120 mesh. Under these conditions, the impact strength, bending strength, and tensile strength of the PLA/PPC/corn straw composites reached 6.21 kJ/m², 52.30 MPa, and 24.12 MPa, respectively, representing improvements of 81.05 %, 41.12 %, and 99.01 % compared to PLA/corn straw composites. FTIR analysis indicated the presence of hydrogen bonding interactions among the composite components. XRD revealed that the incorporation of PPC reduced the crystallinity of the PLA/corn straw composites, thereby contributing to the enhancement of strength and toughness. SEM images demonstrated that the PLA/PPC/corn straw composites neither exhibited cracks typical of PLA/corn straw composites nor displayed pore phenomena commonly observed in PPC/corn straw composites, indicating excellent interfacial compatibility. Therefore, this work provides a theoretical foundation for the industrial development of biodegradable composites.