As a biodegradable and renewable material, poly(lactic acid) (PLA) has attracted numerous attention for its excellent biocompatibility and mechanical performance (high strength and high modulus). PLA matrix biocomposites have been seriously blocked by its poor ductility, low impact strength, low crystallization rate and low crystallinity since it entered people's eye shot. Continuous efforts have been put into the modification research of PLA in the past ten years, which primarily focus on plasticizing, strengthening and toughening. Specifically speaking, plasticizing modification is adding the small molecular compound like lactic acid oligomer, citrate and polyethylene glycol into PLA, for the sake of reducing the interaction between PLA chains, improving the plasticity of PLA, and increasing the elongation at break. Yet the plasticizers are likely to exude and migrate, which is a crucial problem now. Reinforcement modification, namely heterogeneous nucleation of PLA with inorganic fillers or nanoparticles like silica (SiO2), titanium dioxide (TiO2), calcium carbonate (CaCO3), talcum powder (Talc), montmorillonite, which can improve the crystalline properties of PLA, but can not fundamentally enhance the brittleness of the material toughening modification refer to the addition of rubber particles or thermoplastic elastomer such as natural rubber (NR), thermoplastic polyurethane (TPU), polycarbonate (PC) into PLA. Although the toughness of the composite is improved to some extent, the biodegradability cannot be preserved. With the production of some degradable polyester including polycaprolactone (PCL), poly (butylene succinate) (PBS), poly (butylene adipate-co-terephthalate) (PBAT), PLA can be effectively toughened without sacrificing the degradation performance. It is the main direction and research hotspot of PLA modification. PBAT, a degradable polyester polymer, possesses the flexibility of aliphatic hydrocarbon and the rigidity of aromatic ring, which makes PBAT emerge as the best candidate for PLA toughening. In the early research of PLA/PBAT, it was found that the poor compatibility of PBAT and PLA resulted in unsatisfactory mechanical properties of the blends, which is primarily caused by the tremendous differences in the structure of molecular chain segment. In the last decade, on the basis of polymer blending modification, researchers have selected the appropriate third component to modify the PLA/PBAT blend system, and achieved fruitful results. Presently, the impact strength of the PLA/PBAT blend system after toughening has been raised from 2.3 kJ/m2 to 61.9 kJ/m2. This review offers a retrospection of the research efforts with respect to the progress of modification PLA/PBAT blends, and provides elaborate descriptions about physical blend (inorganic filler or nanoparticles and physical compatibility agent) and reactive blending compatibilizer modified PLA/PBAT blends. Finally, we focus on the problems faced by PLA/PBAT blending modification system, aiming at providing a reference for the preparation of high performance fully biodegradable PLA/PBAT composites. © 2019, Materials Review Magazine. All right reserved.
