Super-tough and flame-retardant poly(lactic acid) materials using a phosphorus-containing malic acid-based copolyester by reactive blending

It is a great challenge to simultaneously prepare flame-retardant and super-tough poly(lactic acid) (PLA) materials. Herein, we reported a facile approach that PLA reactively blends with phosphorus-containing copolyester. In this paper, a quinary aliphatic copolyester (PPE) containing phosphorus and pendent hydroxyl group was synthesized with sebacic acid, dimethyl malate, diethyl phosphite, 1,6-hexanediol, and 1,3-propanediol by polycondensation. Then, flame-retardant and super-tough PLA materials (PLA/PPEU) can be achieved by reactively blending with PPE and hexamethylene diisocyanate. The results showed that the toughness of PLA was significantly enhanced. The maximum notched impact strength is 75.3 kJ/m(2) indicated a super toughness performance. Meanwhile, the flame retardance of the PLA was improved obviously. The limited oxygen index (LOI) of PLA increased from 20 to 26%. Moreover, the PLA blends can pass the UL-94 V-0 rating. In addition, both the total heat release and total smoke production of PLA were decreased. The resultant super-tough and flame-retardant PLA materials could be widely applied in electrical and electronic equipment. (C) 2022 Elsevier Ltd. All rights reserved.