Synthesis and thermal characterization of polybenzoxazines based on acetylene-functional monomers

The high thermal stability of this class of polybenzoxazines is a combined result of polymerization of acetylene terminal functional group and oxazine ring-opening polymerization. The high char yield achieved for this class of materials is in the range of 71-81% by weight at 800 degrees C in a nitrogen atmosphere and 30% by weight at 700 degrees C in air as it is determined by thermogravimetric analysis (TGA). Temperature at 10% weight loss (T-10%) is in the range of 520-600 degrees C. The polymerization and post-cure reactions of these benzoxazines are studied by differential scanning calorimetry (DSC). The char formation of the blend of an acetylene-functional benzoxazine with an analogous benzoxazine without acetylene group is also studied by TGA. (C) 1999 Elsevier Science Ltd. All rights reserved.