Customized thermoplastic polyhydroxyurethanes synthesized from ene-containing cyclic carbonates, dithiols and diamines: design, mechanical properties and applications in adhesives

Abstract

Three types of bicyclic carbonates have been synthesized via the thiol–ene coupling of ene-containing cyclic carbonate and dithiols. A series of thermoplastic polyhydroxyurethanes (PHUs) have been synthesized from bicyclic carbonates, isophorondiamine (IPDA) and 1,10-diaminodecane (DAD). The thermo-mechanic and self-healing properties of the PHUs can be tailored simply by changing the feed ratio of the IPDA and the structure of the bicyclic carbonate monomer. Due to the rigid and asymmetrical structure of IPDA, the PHUs with a 6/4 molar ratio of IPDA/DAD have a nearly 100% self-healing efficiency following treatment at 60 °C for 24 h and a tensile strength of 3.79 MPa. An increase in the chain length of the bicyclic carbonate leads to PHUs with a rubber-like state, resulting in poorer mechanical properties. Based on their hydrogen bonding interactions, these PHUs can be applied as pressure-sensitive adhesives at low temperatures.