Enhanced Mechanical Properties of PET-Based Thermoplastic Elastomers: Brittle–Ductile Transition via Micro Cross-linking Technology

A novel micro cross-linking technology is proposed to enhance the mechanical properties of poly(ethylene terephthalate) (PET)-based thermoplasctic elastomers (TPEEs) whose molecular weights are difficultly increased via traditional synthetic technologies. It is found that the brittle fractures of TPEEs, usually observed in polymers with low molecular weights, can be converted into ductile form with the introduction of a certain fraction of 1,2,3,4-butane tetracarboxylic acid as a cross-linking agent. Unlike the traditional cross-linking technologies, which usually cause the elastomers to suffer the deficiencies of extremely high stiffness, inherent weakness, and the inability to be efficiently reused, TPEEs still maintain their elastomeric characteristics well with the incorporation of micro cross-linking structure and are endowed with a well-defined microphase-separated structure, excellent tensile properties, and the abilities to be melt-processed and reused. This work offers a new guideline to improve the mechanical properties for polymers with relatively low molecular weights.