A well-defined biodegradable 1,2,3-triazolium-functionalized PEG-b-PCL block copolymer: facile synthesis and its compatibilization for PLA/PCL blends

A novel biodegradable 1,2,3-triazolium-functionalized PEG-b-PCL copolymer (TAPEC) was synthesized by the “click” coupling of methoxypolyethylene glycol azide and α-propargyl-ω-hydroxyl-poly(ε-caprolactone), followed by the quaternization of the 1,2,3-triazole moiety with iodomethane. All the intermediates and TAPEC were characterized by 1H NMR, FT-IR, and gel permeation chromatography (GPC). Taking advantage of the characteristics of ionic liquid and block copolymer, this ion-containing diblock copolymer is expected to be used as a novel compatibilizer in mixed biopolyester for regulating the interface and crystallization behaviors. Hence, the TAPEC was evaluated as a compatibilizer and an interface emulsifier in the blends of polylactic acid (PLA) and poly(ε-caprolactone) (PCL). Non-isothermal crystallization experimental results showed that the TAPEC with the higher amount of ε-caprolactone units induces a plasticization and nucleate effect that increased the crystallization ability of the PLA phase; meanwhile, in the PCL phase, the agminated ionic cluster acting as a nucleating agent significantly increased the crystalline of PCL.