Covalent Adaptable Network with High Topology Freezing Temperatures and Tunable Mechanical Properties: Polyureas Containing Dynamic Aniline–Urea Bonds
Jiaxin Shi, Tianze Zheng, Jinjing Guo, Baohua Guo, Jun Xu
Abstract
Most of the reported dynamic chemically cross-linked polymers, especially elastomers, have a low or mediate topology freezing temperature so that they will creep at high temperatures. In this study, via the bulk polymerization of commercial feedstocks such as aromatic amine-terminated polytetrahydrofuran and isocyanates, we obtained a family of polyureas with dynamic aniline–urea bonds varying from rigid plastics to elastomers. The dynamic polyureas exhibit vitrimer-like properties due to the low degree of network dissociation, possessing high topology freezing temperatures (over 170 °C) and thermal stability. The polyureas based on dynamic bonds can be used for functional applications, such as surface grafting and thermoadaptive shape memory. The aniline–urea network provides a strategy for the preparation of high-performance recyclable functional polymers.