Syntheses of copolymers containing pendant cyclic iminoethers and crosslinking reactions of these copolymers with dithiols and dicarboxylic acids

Copolymers containing pendant cyclic iminoethers were prepared by radical copolymerizations of 2‐vinyl‐2‐oxazoline (VOZO), 5‐methyl‐2‐vinyl‐2‐oxazoline (MVOZO), 4,4‐dimethyl‐2‐vinyl‐2‐oxazoline (DMVOZO), 4,4‐dimethyl‐2‐vinyl‐5,6‐dihydro‐4H‐1,3‐oxazine (DMVOZI), and 4,4,6‐trimethyl‐2‐vinyl‐5,6‐dihydro‐4H‐1,3‐oxazine (TMVOZI) with styrene, methyl methacrylate (MMA), and ethyl acrylate (EA) using AIBN as an initiator. In addition, the monomer reactivity ratios of VOZO, MVOZO, DMVOZO, and DMVOZI with styrene and MMA were determined. The crosslinking reactions of these copolymers with polyfunctional thiols such as 6‐(N,N‐dibutyl)amino‐1,3,5‐triazine‐2,4‐dithiol (DBDT), 4,4′‐oxydi(benzenedithiol) (OBDT), and pentaerythritol tetrathioglycolate (PETT), and dicarboxylic acids such as succinic acid, adipic acid, and sebacic acid were carried out at several reaction temperatures. From these results, it was found that the order of reactivity of pendant cyclic iminoethers to the thiols was VOZO > DMVOZO ≥ DMVOZI > MVOZO > TMVOZI, and that of the cyclic iminoethers to the carboxylic acids was VOZO > MVOZO ≥ DMVOZI > TMVOZI ≥ DMVOZO. Furthermore, the order of reactivity of the thiols to the cyclic iminoethers was DBDT > OBDT > PETT, and that of the dicarboxylic acids to the cyclic iminoethers was succinic acid > adipic acid > sebacic acid.