分别使用熔融法、溶液法和三步法制备了间氨基苯甲腈/苯酚型苯并恶嗪单体,采用1H-NMR、IR、GPC和DSC比较了3种产物结构与固化行为的差异,使用TGA和DMA研究了3种聚苯并恶嗪的热稳定性和动态热机械性能。结果表明,通过三步法得到的单体的纯度最高,其聚合物的热稳定性能及动态热机械性能最为优异,5%失重温度为320℃,800℃氮气下的残炭率达到58%,玻璃化转变温度为199℃。
The m-aminobenzonitrile/phenol-type benzoxazine monomers were synthesized using the melting method, solution method and three-step method,respectively. The differences of the structure and curing behaviors were compared by 1H-NMR, IR, GPC and DSC. The thermal stability and thermal mechanical property of three polybenzoxazines were studied by TGA and DMA. The results showed that the monomer synthesized by three-step method had the highest purity and its polymer had the best thermal stability and thermal mechanical property. The 5% weight loss temperature, char yield at 800℃ under N2 and the Tg were 320 ℃, 58%, 199℃, respectively.