Promoting effects of urethane derivatives of phenols on the ring‐opening polymerization of 1,3‐benzoxazines

For the purpose of reducing the induction period of the ring‐opening polymerization of N‐methyl‐1,3‐benzoxazines, several urethanes were examined as promoters. The examined promoters 3a – d were the adducts of resorcinol and phenyl isocyanate, that of bisphenol A and phenyl isocyanate, that of resorcinol and butyl isocyanate, and that of 1,3‐propanediol and phenyl isocyanate, respectively. The aromatic urethanes 3a and 3b , which were adducts of the phenolic compounds and phenyl isocyanate, exhibited significant promoting effects. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011