热熔型BA221氰酸酯树脂的固化动力学及流变行为

Curing Kinetics and Rheological Behavior of Hot-Melt BA221 Cyanate Ester Resin

氰酸酯(CE)树脂具有高度对称的化学结构和强结晶性,固化反应温度高,固化物脆性大,容易从预浸料中结晶析出并悬浮于表面,严重影响了预浸料的表观质量、制备工艺和力学性能。文中采用F-51酚醛环氧改性CE树脂,通过预聚工艺制备了一种室温下为半固态、成膜性好、适用期长、适用于热熔法预浸料工艺的热熔型CE树脂(代号BA221)。采用差示扫描量热法研究了BA221树脂的固化动力学和固化反应参数,获得了固化动力学方程,优化了固化制度,活化能较CE树脂降低了66.9%。采用流变法研究了BA221树脂的黏度变化规律,确定了热熔型BA221树脂的制膜温度为80℃,获得了成膜性和延展性良好的热熔胶膜。BA221树脂固化物的玻璃化转变温度为268.4℃,拉伸强度和延伸率分别为79.7 MPa和3%,弯曲强度和冲击强度分别为122 MPa和21 k J/m2,较CE树脂分别提高了96.3%,134.4%,76%和270%。扫描电镜结果表明BA221树脂固化物为韧性断裂。F-51酚醛环氧改性CE树脂效果显著,实现了CE树脂在120℃预聚、80℃成膜和180℃后固化的工程化应用目标,为制备热熔法预浸料提供了一种耐高温CE树脂。

Cyanate ester(CE)resin has highly symmetrical chemical structure and strong crystallinity,high curing reaction temperature,and high brittleness of cured products.It is easy to crystallize and separate from prepreg and suspend on the surface,seriously affecting the apparent quality,preparation process,and mechanical properties of prepreg.In this paper,F-51 phenolic epoxy modified CE resin was used to prepare a hot melt CE resin(code:BA221).It has the characteristics of good film formation,long shelf life,and is suitable for hot melt prepreg process.The curing kinetics and curing reaction parameters of BA221 resin were studied by differential scanning calorimetry(DSC).The curing kinetics equation of BA221 resin and optimized curing system were obtained.The activation energy of BA221 resin is decreased 66.9%than CE resin.The viscosity variation of BA221 resin was researched by rheological method.The film forming temperature of hot-melt BA221 resin is determined to be 80℃.A hot-melt film with good film forming and ductility was obtained.The glass transition temperature of BA221 resin is 268.4℃.The tensile strength and elongation are 79.7 MPa and 3%,and its bending strength and impact strength are 122 MPa and 21 kJ/m^(2).Comparing with CE resin,it is increased by 96.3%,134.4%,76%and 270%,respectively.The results of scanning electron microscopy(SEM)show that the cured BA221 resin exhibits ductile fracture.F-51 phenolic epoxy modified CE resin has significant effects,achieving the engineering application goals of prepolymerization at 120℃,film formation at 80℃,and post curing at 180℃.It provides a high temperature resistant CE resin for the preparation of hot melt prepregs.