Synthesis of reactive polyureas bearing vinylcyclopropane moiety in main chain and their radical cross‐linking with multifunctional thiols

Abstract

AbstractA series of polyureas 5a‐c bearing vinylcyclopropane (VCP) moiety in their main chains was synthesized by the polyaddition of diamine 2 bearing VCP moiety with diisocyanates. Upon treatment of polyurea 5b with thiols in the presence of azobisisobutyronitrile (AIBN), the VCP moieties in the polymer main chain efficiently reacted with the thiols via a sequence of the radical addition of thiol to the vinyl group and the ring opening of the cyclopropane ring, yielding the corresponding networked polymers 9–11. The thermogravimetric analysis of the networked polymers 9–11 revealed that their residual weight at 350 °C was higher than that of the precursor polyurea 5b.