2024 Volume 60 Issue 1 Pages 10-18
In this study, we synthesized thermosets using the fran-protected maleimidobenzoxazine with a 2-ethylhexyl group as an N-substituent（fMB）and the thiol-modified silsesquioxanes（SQ107 and SQ183）．First, the adducts of fMB and SQ107 or SQ183 were prepared by the ring-opening reaction of the oxazine ring （COLBERT reaction） at room temperature, then the isolated adducts were heated at 140℃ for 1 h, 150℃ for 2 h, and finally 160℃ for 1 h under 2 MPa pressure conditions in order to obtain thermosets. The 5％ weight-loss temperatures, 50 ％ weight-loss temperatures, maximum decomposition temperatures, and residual weights at 800℃ were determined by the thermogravimetric analysis of the thermosets, and they were compared with the characteristics of the thermosets with the related chemical structures reported in previous papers. Furthermore, the effects of cross-linking structures on mechanical properties of the thermosets produced from fMB and SQ107 or SQ183 as the starting materials were discussed based on the results of viscoelasticity measurements and mechanical tensile tests.
