高纯度双酚S环氧树脂/双氰胺/改性咪唑潜伏体系固化行为和性能研究

Study on curing behavior and properties of high purity bisphenol S epoxy resin/dicyandiamide/modified imidazole latent system

以乙醇溶液中沉淀的方法制备了高环氧值、低氯含量的结晶性双酚S型环氧树脂,利用盐酸-丙酮滴定法、红外、核磁、飞行时间质谱(MALDI-TOF)等手段对树脂的分子结构和环氧值等进行分析表征。以双氰胺为固化剂,采用DSC、TGA、DMA等分析手段对固化行为及固化物性能进行表征。研究结果表明:合成的双酚S环氧树脂纯度高,w(氯离子)<0.01%(相对环氧树脂质量而言),环氧值大于0.50(理论值0.55);加入促进剂w(咪唑)=1%(相对环氧树脂质量而言),体系固化温度降低至151.16℃,固化体系活化能84.80 kJ/mol,反应级数0.92,为近似一级反应;固化物导热系数为0.46 W/(m·K),电阻率为4.063×1011Ω·m,玻璃化转变温度为192.86℃;双酚S环氧/双氰胺/咪唑体系是一种热稳定性高、绝缘导热性能良好的潜在电子封装基体树脂材料。

The crystalline bisphenol S-type epoxy resin with high epoxy value and low chlorine content was prepared by precipitation method in ethanol solution. The molecular structure and epoxy value of the resin were characterized by hydrochloric acid-acetone titration,infrared,NMR,time-of-flight mass spectrometry(MALDITOF). Using dicyandiamide as curing agent,the curing behavior and properties of the cured products were characterized by DSC,TGA,DMA and other analytical methods. The research results showed that the purity of synthesized bisphenol S epoxy resin was high,w(chloride ion)<0.01%(relative to the quality of epoxy resin),and the epoxy value was greater than 0.50(theoretical value was 0.55). When adding w(imidazole)=1%(relative to the quality of epoxy resin),the curing temperature of the system was reduced to 151.16 ℃,the activation energy of the curing system was 84.80 kJ/mol,and the reaction order was 0.92,suggesting that the curing reaction was an approximate first-order reaction. The thermal conductivity of cured product was 0.46 W/(m·K),the resistivity was4.063×1011Ω·m,the glass transition temperature was 192.86 ℃. The bisphenol S epoxy/dicyandiamide/imidazole system was a potential candidate of matrix resin applied in electronic packaging with high thermal stability,good insulation and thermal conductivity performance.