Green polymer chemistry: One-pot, metal-free synthesis of macromonomer via direct polycondensation of lactic acid and its radical polymerization to graft and comb polymers

A new and simple method of one-pot two-stage poly(lactic acid) (PLA) macromonomer synthesis has been developed. The first stage of the reaction is a direct polycondensation of lactic acid (LA) without a catalyst to PLA, and the second stage is a ring-opening addition of PLA to glycidyl methacrylate (GMA) to afford a PLA macromonomer with a methacryloyl polymerizable group (GMA-Macro). Both reactions are performed consecutively in one pot. This method produced GMA-Macro with high functionality in high yields and thus far seems the simplest and probably the cheapest way to prepare PLA macromonomers. Furthermore, the method is metal-free, offering considerable advantages for biomedical and pharmaceutical applications. GMA-Macro has been shown to be useful for the preparation of PLA graft copolymers in solution or in miniemulsion and of PLA comb polymers in solution. LA is a biobased renewable feedstock. Thus, this method provides a good opportunity to conduct ‘green polymer chemistry’. A new facile method of poly(lactic acid) (PLA) macromonomer synthesis has been developed by using one-pot two-stage reaction synthesis. The first stage reaction is a direct polycondensation of lactic acid without catalyst to PLA, and the second stage is a ring-opening addition of PLA to glycidyl methacrylate to afford a PLA macromonomer having methacryloyl polymerizable group. [Display omitted] •One-pot, metal-free synthesis of poly(lactic acid) macromonomer is developed.•This new method utilizes direct polycondensation of lactic acid.•The method is the simplest and probably the cheapest for the macromonomer synthesis.•The macromonomer produced graft and comb polymers as the previous ones did.•The macromonomer can be used in place of the previous expensive ones from lactide.