Reactive & Functional Polymers, Vol.73, No.11, 1544-1552, 2013
Synthesis of itaconimide/nadimide-functionalized benzoxazine monomers: Structural and thermal characterization
A novel series of itaconimide/nadimide-functionalized benzoxazine monomers (I-Bz/N-Bz) from imide-terminated amines, paraformaldehyde and phenol/m-cresol/cardano1/4-(hydroxyphenyl) benzoxazole were synthesized and characterized by FT-IR, H-1 and C-13 NMR and HRMS analyses. The I-Bzs exhibited lower curing temperatures compared to the N-Bzs, which may be attributable to the presence of the 1,1-disubstituted double bond in itaconimide. The poly(I-Bz)s exhibited higher glass-transition temperatures (210-216 degrees C) compared to the poly(N-Bz)s (151-178 degrees C). The itaconimide- and nadimide-functionalized benzoxazines showed comparable thermal stability, but differences in their phenolic structures affected their thermal behavior (char yield and T-max). The poly(I-Bz)s (19-47%) showed higher char yields compared to the poly(N-Bz)s (18-41%), depending on the backbone structure. The highest lap-shear strength at 200 degrees C was observed in I-Bz/N-Bz derived from m-cresol. (C) 2013 Elsevier Ltd. All rights reserved.