Super‐ductile and stiff PBAT / PLA biodegradable composites balanced with random PMMA‐ co ‐GMA copolymer as compatibilizer

Poly(butylene adipate–butylene terephthalate) (PBAT) and poly(lactic acid) (PLA) biodegradable composites have been prepared by the melt-blending method using a new methyl methacrylate and glycidyl methacrylate random copolymer (MG) as compatibilizer. The compatibilization reaction between the epoxy functional groups in MG and the carboxyl groups in PBAT and PLA resulted in the formation of branched PBAT-co-MG-co-PLA macromolecules and improved compatibility. The compatibilization effect induced higher glass transition temperature for PBAT and PLA. The addition of MG had little influence on the melting process of PBAT. However, the fine miscibility between PLA and MG inhibited cold crystallization and the following melting behavior of PLA. The compatibilization effect promoted the uniform dispersion and smaller particle size of the PLA phase, which enhanced the heterogeneous nucleation effect of PLA and induced higher crystallization temperature of PBAT. Dynamic rheological tests showed that PBAT/PLA/MG blends exhibited higher complex viscosity and modulus than PBAT and PBAT/PLA blend, proving the improved interfacial interaction and melt strength. Compared with the PBAT/PLA composite, PBAT/PLA/MG blends showed much better ductility and stiffness balance because of the compatibilization effect of MG. When MG concentration was 6 wt%, the blend achieved a maximum strain of 694% and tensile strength of 49.3 MPa, which were 1.8 and 4.3 times higher than those of the PBAT/PLA composite. © 2022 Society of Industrial Chemistry.