Synthesis And Properties Of ABA-type Thermoplastic Elastomers With Lysine-based Polyesters As Soft Block

Thermoplastic elastomer(TPE)is a functional polymer material with both thermoplastic and elastomeric properties.They usually comprise two incompatible segments with different chemical structures,an ambient-flexible segment and hard segments that can form physical cross-links.The hard block is usually the semicrystalline polymer or amorphous polymer with high glass transition temperature(Tg).The soft block is generally the amorphous polymer with low glass transition temperature(Tg).Due to this unique construction,TPEs can be melt-processed at high temperature,while at lower temperature they function as elastomers,showing obvious elastic recovery from large deformations without fracture.In this article,Novel renewable thermoplastic elastomers were synthesized by sequential polymerization of lysine-and itaconic acid-derived monomers.Three poly(N-Phenylitaconimide)-b-polyester-b-poly(N-Phenylitaconimide)(PPhII-PL-PPhII)triblock copolymers were prepared containing 12-25mol%.The properties of the obtained triblock copolymer are evaluated as high-performance and renewable thermoplastic elastomer materials.Its specific contents include the following aspects:Firstly,Novel renewable thermoplastic elastomers were synthesized by sequential polymerization of lysine-and itaconic acid-derived monomers.Ring-opening polymerization of lysine-based O-carboxyanhydride(OCA)monomer using diethylene glycol as an initiator gave well-defined ?,?-dihydroxy functionalized lysine-derived polyesters(HO-PL-OH).The Mn of these polyesters increased with the monomer conversion while retaining relatively narrow molecular weight distributions.Second,Based on the successful controlled polymerization and esterification of ?,?-dihydroxy with 2-bromoisobutyryl bromide,the resultant Br-PL-Br macroinitiator was used for the atom transfer radical polymerization of N-Phenylitaconimide(PhII).At last,three poly(N-Phenylitaconimide-b-polyester-b-poly(N-Phenylitaconimide)(PPhII-PL-PPhII)triblock copolymers were prepared containing 12-25 mol % PPhII,as determined by 1H NMR spectroscopy.The properties of the obtained triblock copolymer are evaluated as high-performance and renewable thermoplastic elastomer materials.