基于差示扫描量热分析和流变探究环氧大豆油增韧环氧树脂的固化过程

以聚醚胺D230为固化剂,研究了不同环氧大豆油含量(占双酚A型环氧树脂E-44的5%,10%,15%)增韧环氧树脂固化体系的反应动力学理论及流变行为。通过升温非模型中的KAS法对环氧树脂固化体系的差示扫描量热分析数据进行了研究,得出了固化动力学参数随体系环氧大豆油含量和升温速率的变化规律,并发现该反应由初期的无催化转向自催化反应,最后阶段则由化学控制转为扩散控制。通过旋转流变仪对环氧树脂固化过程进行流变分析,升温流变结果表明,体系中含有的环氧大豆油含量越多,凝胶点出现的时间越早;等温流变结果则表明,温度越高,凝胶点出现的时间越早;同时流变分析也表明,反应后期由于体系黏度过大,反应会由化学控制转变为扩散控制。通过计算,可得出环氧大豆油质量占环氧树脂10%的固化体系凝胶活化能为54.75kJ/mol。

Curing Process of Epoxy Resin Toughened with Epoxy Soybean Oil Investigated by Differential Scanning Calorimetric and Rheological

Based on DSC measurement,kinetics of the reaction of bisphenol A-based epoxy resin cured with polyether amine (D230) in the presence of three different loadings (5％,10％ and 15％) of epoxidized soybean oil (ESO) was studied.Nonisothermal differential scanning calorimetric (DSC) and free-model isoconversional method were used to analyze the curing kinetic data and calculate the activation energy of the reaction.The results show that the extent of curing of samples containing 5％ ESO,10％ ESO,and 15％ ESO complied with the autocatalytic model in the early stages.It is also found that the curing reactions are diffusion control at the final stage of the reaction.The epoxy resin curing process was then analyzed through the rotational rheometer.Under the nonisothermal condition,the theological results show that the more content of ESO in the system,the sooner the gel point,meanwhile;under the isothermal condition,the rheological results show that the higher the temperature,the sooner the gel point.Besides,both kinds of rheological results show that the reaction is controlled by diffusion control instead of chemistry control in the later stage of the reaction,due to the high viscosity.The gel activation energy of curing reaction is obtained (54.75 kJ/mol).