Impact of reactive compatibilizers on the properties of poly(lactic acid)/bamboo flour composites

The preparation of biodegradable wood plastic composites using polylactic acid (PLA) as the matrix and plant flours as the reinforcing phase aligns with the principles of sustainable development. However, there is a large polarity difference and poor compatibility between PLA and plant flours. To improve the performance of PLA/bamboo flour (BF) composites and simplify the process, this study modified PLA using glycidyl methacrylate (GMA), methacrylic acid (MAA), and maleic anhydride (MAH) as reactive compatibilizers. Composites were prepared from the modified PLA and BF using the hot-pressing method. The results indicated that all three reactive compatibilizers increased the polarity and surface free energy of PLA. GMA, MAA, and MAH were successfully grafted onto the PLA molecular chain, resulting in the formation of PLA-g-GMA, PLA-g-MAA, and PLA-g-MAH graft copolymers. In addition, the interfacial compatibility between PLA-g-GMA and BF was the best, and the PLA-g-GMA/BF composite had the lowest 24 h water absorption (2.17%). Furthermore, the PLA-g-GMA/BF composite showed the highest bending, tensile and impact strengths of 33.3 MPa, 14.7 MPa, and 1.33 kJ/m2, respectively, which were 63.8%, 104.9% and 4.7% higher than those of untreated PLA/BF composites, respectively.