Preparation of copolyester elastomers by introducing a lactic acid-based monomer with enhanced mechanical properties via micro-crosslinking

Abstract

A series of novel degradable copolyester elastomers (PBLT) were synthesized through a two-step method of esterification and polycondensation using succinic acid ethyl lactate (SLA), 1,4-butanediol (BDO), and dimethyl terephthalate (DMT) as monomers. The DSC results show that the introduction of SLA monomers disrupts the overall crystallization performance of the copolyesters. Moreover, with the increase of the SLA component, the copolyester undergoes a transition from plastic to elastomer, but its mechanical properties are inevitably damaged. Therefore, glycerol was used for the micro-crosslinking treatment of the PBLT elastomer. The results of DSC and TGA tests indicate that the micro-crosslinking has no obvious influence on the crystallization performance and thermal stability of the PBLT elastomer. The mechanical property and cyclic recovery tests show that the micro-crosslinking can significantly improve the overall modulus and strength of the PBLT elastomer while slightly sacrificing the resilience performance. Additionally, the degradation experiment shows that the micro-crosslinked sample only loses a small part of its degradation ability and can still maintain excellent degradation performance after micro-crosslinking. This study proposed a simple and effective method to directly use lactic acid as a monomer for the design and synthesis of a series of thermoplastic elastomers with excellent properties, providing new ideas for the preparation of degradable thermoplastic copolyester elastomers.