Thermoresponsive crosslinked isocyanate-free polyurethanes by Diels-Alder polymerization

This new study is a continuation of our previous work on thermocleavable nonisocyanate polyurethanes (NIPUs), but it is focused on crosslinked networks. Two systems are studied: the first system involves a dicyclocarbonate adduct with a PPO-bicyclocarbonate and a triamine as crosslinker. The second system involves a tetracyclocarbonate DA adduct as crosslinker with the same PPO-bicyclocarbonate and a difunctional amine. Firstly, Diels-Alder adducts are synthesized and characterized. Then they are copolymerized to yield two types of cleavable polymer networks. The thermal behavior of synthesized polymers is fully characterized. Finally, by SEC, it was demonstrated that the obtained NIPU polymer chains are sliced up by rDA reaction. (C) 2016 Wiley Periodicals, Inc.