Adaptable thermoset polymers with internal dynamic bonds, and methods of making and using the same

Abstract

The disclosed technology provides improved thermoset vitrimers. It has been discovered that by incorporating adaptable dynamic groups along the polymer backbone, along with permanent, non-dynamic crosslinking points, an improved thermoset vitrimer is generated. In some variations, a thermoset vitrimer comprises: a linear polymer backbone containing associative dynamic covalently bonded species; a crosslinked network containing non-dynamic branch points; and non-dynamic species between non-dynamic branch points and terminal ends of the linear polymer backbone. Some methods comprise: reacting a linear prepolymer with an amine-containing species to form an amine-terminated linear prepolymer; reacting the amine-terminated linear prepolymer with an isocyanate-containing species to form an isocyanate-endcapped linear prepolymer; mixing the isocyanate-endcapped linear prepolymer with a reactive crosslinking agent having a crosslinking functionality of at least 3; and curing the isocyanate-endcapped linear prepolymer with the reactive crosslinking agent, thereby forming a thermoset vitrimer. Experimentally produced thermoset vitrimers demonstrate the ability for self-repair at elevated temperature.