双马来酰亚胺对苯并恶嗪共聚物热稳定性的影响

Effect of bismaleimide on the thermal stability of benzoxazine copolymers

将双马来酰亚胺（BMI）引入丁香酚／4，4＇-二氨基二苯甲烷型苯并恶嗪（e—ddm）与双酚A/苯胺型苯并恶嗪（b-a）、苯酚／4，4＇-二氨基二苯甲烷型苯并恶嗪（p-ddm）及苯酚，苯胺型苯并恶嗪（p-a）混合物中。采用红外光谱，示差扫描量热分析及热重分析研究了其对苯并恶嗪共聚物热稳定性的影响。结果表明，BMI中的马来酰亚胺基团可与e—ddm中的烯丙基优先发生ene反应，从而抑制了e—ddm的挥发，可制得无泡孔的聚苯并恶嗪。但ene反应也抑制了e—ddm链的活动性，使得e—ddm与b-a、p-ddm和P—a中苯酚或苯胺对位的反应减少。BMI的引人可提高e—ddm与b-a或p-ddm、p-a共聚物的初始热稳定性，但也降低了苯并恶嗪的聚合能力，使其固化物的800℃残炭率有所下降。

The bismaleimide （BMI）was introduced into the eugenol/4,4 ＇-diaminodiphenylmethane benzoxazine （e-ddm ） and bisphenol A/aniline benzoxazine （ b-a ）, phenol /4,4＇-diaminodiphenylmethane type benzoxazine （ p-ddm ） and phenol/ aniline type benzoxazine （p-a ）mixture. The effect of BMI on the thermal stability of benzoxazine copolymers were investigated by infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. The results showed that the maleimide group in BMI could preferentially react with the ally group in e-ddm to inhibit the volatilization of e-ddm, and cell-free polybenzoxazine could be obtained. However, the the activity of the e-ddm chain was also inhibited by the ene reaction, resulting in a decrease in the reaction of e-ddm with the para-position of phenol or aniline in b-a, p-ddm and p-a. The initial thermal stability of e-ddm and b-a or p-ddm, p-a copolymers could be improved by the introduction of BMI, but the polymerization ability of benzoxazine was reduced, so that the char yield of cured product of 800 ℃ was decreased.