Tough and Thermostable Polybutylene Terephthalate (PBT)/Vitrimer Blend with Enhanced Interfacial Compatibility

Polymer blending is an efficient way to obtain extraordinary polymeric materials. However, once permanently cross-linked thermosets are involved in blending, there are challenges in designing and optimizing the structures and interfacial compatibility of blends. Vitrimer with dynamic covalent polymer networks provides an innovative opportunity for blending thermoplastics and thermosets. Herein, a reactive blending strategy is proposed to develop thermoplastic-thermoset blend with enhanced compatibility on the basis of dynamic covalent chemistry. Specifically, polybutylene terephthalate (PBT) and polymerized epoxy vitrimer can be directly melt blended to obtain tough and thermostable blends with desirable microstructures and interfacial interaction. Bond exchange facilitates the grafting of PBT and epoxy vitrimer chains, thus enhancing the interfacial compatibility and thermal stability of blends. The obtained blend balances the strength and stretchability of PBT and epoxy vitrimer, resulting in enhanced toughness. This work offers a new way of designing and fabricating new polymeric materials by blending thermoplastics and thermosets. It also suggests a facile direction towards upcycling thermoplastics and thermosets.

Automated summary

A reactive blending strategy was proposed to develop a thermoplastic-thermoset blend with enhanced compatibility based on dynamic covalent chemistry. Polybutylene terephthalate (PBT) and polymerized epoxy vitrimer were melt blended and the bond exchange facilitated the grafting of PBT and epoxy vitrimer chains, resulting in improved interfacial compatibility and thermal stability. The obtained blend achieved a balance between the strength and stretchability of PBT and epoxy vitrimer, leading to enhanced toughness.