High flame retardant and heat-resistance, low dielectric benzoxazine resin with phthalimide structure

In order to improve the thermal stability, flame retardancy and dielectric properties of benzoxazine resin, benzoxazine resins with different content of 4,4′-‍(hexafluoroisopropylidene) diphthalic dianhydride(m-EFDA) were prepared by crosslinking alkynyl groups. The results showed that benzoxazine can improve the processing window of m-EFDA, while m-EFDA was beneficial to improve the thermal stability and dielectric properties of benzoxazine resins. The T_d5% of PBZFI-50 reached 418.2°C, T_d10% was up to 457.3°C, D_k was 2.89 and D_f was as low as 0.013 at 1MHz. The chemical structures of volatile products from the pyrolysis of benzoxazines resin at different temperatures were identified by TG-FTIR and Py-GC/MS, and the promoting effect of m-EFDA on improving the thermal stability was confirmed. Compared with pure benzoxazine resin, the resin containing m-EFDA has great performance improvement, which is expected to be used as high temperature and low dielectric material in aerospace and microelectronics field.