Low temperature polymerization of novel,monotropic liquid crystalline benzoxazines

Cationic ring opening polymerization at a lower temperature range/faster polymerization than ordinary benzoxazine resins has been achieved without added initiators or catalysts via liquid crystalline (LC) benzoxazine resins. Faster polymerization is observed even above the liquid crystal forming temperature. The FTIR spectra show that opening of the oxazine ring occurs even at 110 °C generating phenolic groups that auto‐catalyzed the cationic polymerization of the monomer increasing the rate of polymerization. The newly formed H‐bonds inhibit the formation of LC phases after polymerization. Some of the monomers show nematic LC transitions upon cooling. None of them showed LC transitions during the heating cycle, exhibiting monotropic LC phases. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5871–5881, 2009