Benzoxazine resins are promising to be a kind of high performance thermosetting resin because of their excellent performances and good processability. One of their advantages is that no by-products are released during the curing process due to the ring-opening reaction of the oxazine rings. However, we still found that a few of volatiles were produced and the weight loss occurred during cure, which can cause the foaming of the cured samples. In this work, the weight loss mechanism of benzoxazine monomer, BA-a, during cure with heat or catalysts were studied. TGA and DSC were used to study the relationship between curing reaction temperature and weight-loss reaction temperature. In-situ FTIR tests were taken to study the evolution of chemical structures of BA-a and BA-a/catalysts during cure. Their volatiles during cure were trapped and characterized by FTIR, <sup>1</sup>H-NMR and <sup>13</sup>C-NMR. The results showed that the generation of the volatiles resulted mainly from the fracture of intermediates formed by the ring-opening reaction. Furthermore, the weight loss mechanisms were different for BA-a with different catalysts.

Study on the weight loss of benzoxazine during the curing process

255th National Meeting (2018)

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