摘要
Fiber-reinforced phenolic composite has become an ideal material for solid rocket motor’s(SRM)nozzle,because of its excellent high temperature resistance and ablation resistance.The physical and chemical properties of reinforcing fiber would significantly affect the cure reaction of phenolic(PF)resin,which results in the obvious difference between the cure characteristics of the fiberreinforced phenolic system and neat resin.To clarify the difference in cure reaction between fiber-reinforced phenolic system and PF resin,meanwhile,to obtain the kinetics of high silica glass fiber/phenolic(GF-HSi/PF)prepreg and carbon fiber/phenolic(CF/PF)prepreg,the dynamic experiments of PF resin,GF-HSi/PF prepreg and CF/PF prepreg are carried out by differential scanning calorimetry(DSC).Iso-conversional kinetics is proposed,and the activation energy is determined as a function of cure degree.The reaction model f(α)is obtained by introducing the kinetics compensation effect,founding that the f(α)of PF resin is influenced significantly by reinforcing fiber.The kinetics of three materials are determined by the model-fitting method,founding that the kinetic models of PF resin,GF-HSi/PF prepreg and CF/PF prepreg are a one-step autocatalytic model,two-step model from autocatalytic reaction to N-order reaction and three-step model from autocatalytic reaction to N-order reaction respectively.
纤维增强酚醛复合材料以其优异的耐高温和耐烧蚀性能成为固体发动机喷管的理想材料.增强纤维的物理和化学特性会显著影响酚醛树脂(PF)的固化反应,为探究纤维增强酚醛体系固化反应与纯酚醛的区别,并获得高硅氧玻璃纤维/酚醛预浸料和碳纤维/酚醛预浸料的固化模型,本文采用差示扫描量热法(DSC),分别对纯酚醛树脂、高硅氧玻璃纤维/酚醛、碳纤维/酚醛进行了动态DSC实验.针对三种材料的动态DSC测量结果,通过等转变动力学方法,确定了3个反应体系的活化能随固化过程的变化规律,并通过引入动力学补偿效应,获得了3种材料的固化反应机理.结果表明,增强纤维会改变酚醛树脂的固化反应机理,三者的活化能和指前因子都不同,纯酚醛树脂为自催化模型,高硅氧玻璃纤维/酚醛预浸料为由自催化反应转变为N阶反应的两步模型,碳纤维/酚醛预浸料为由自催化反应转变为N阶反应的三步模型.
基金
This work was supported by the National Natural Science Foundation of China(Grant No.U1837601).
