Abstract
In recent years, benzoxazines have been reported as a novel high performance thermosetting resin with ring-opening reactivity, which has superior properties such as high heat-resistance and glass transition temperature (Tg). Inthisstudy, new series of bi-functional benzoxazines were synthesized from aromatic diamines, and their properties such as hardening behavior, thermal and mechanical properties were examined. The benzoxazines exhibited exothermic reactivity at a temperature range of 220～230℃. The 5% weight loss temperatures of cured benzoxazines were 320～350℃. The benzoxazines showed higher residual weights at 700℃, compared with bi-functional benzoxazines derived from bisphenols. The Tg and crosslinking density were analyzed and calculated from the results of the dynamic mechanical analysis. The Tg of benzoxazine depended on the spacer structure. In addition, the Tg of benzoxazine became higher with increase of crosslinking density. The storage modulus at ordinary temperature was lowered with decrease of crosslinking density.
