A New Healable Polymer Material based on Ultrafast Diels-Alder ‘Click’ Chemistry using Triazolinedione and Fluorescent Anthracyl Derivatives; A Mechanistic Approach
Since the last decade, the synthesis of self-healable polymers using Diels-Alder (DA) ‘click’ chemistry has been one of the major focus in the chemical community. The reversible covalent DA linkages lead to produce several materials which can be applicable from biological to industrial fields. Herein, we report a new type of healable fluorescent polymer material based on anthracene and 1,2,4-triazoline-3,5-dione (TAD) system which has several advantages over conventional bismaleimide based DA reaction. In this case, reversible addition fragmentation chain-transfer (RAFT) polymerization technique was employed to prepare copolymers of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA). The methacrylate copolymers bearing repeating pendant hydroxyl groups were coupled with anthracyl derivatives, where the aromatic groups acted as the ‘click’ partner to TAD moiety. The addition of TAD derivative to the anthracyl-modified copolymers led to produce an ultrafast crosslinked network at ambient conditions without any need of modular reagents. The rationalization of ultrafast DA reaction mechanism of TAD-anthracene systemwas carried out via density functional theory (DFT) calculations by taking different anthracene and TAD derivatives. Thermoreversible properties and healing characteristics were analyzed by DSC and microscopic analyses.