超支化环氧/双酚A环氧杂化树脂的固化反应动力学

通过一步法合成了一种低黏度的芳香族超支化环氧树脂(HTME-2),并与双酚A环氧树脂(DGEBA)杂化制备了超支化环氧/双酚A环氧杂化树脂(简称杂化树脂),研究了杂化树脂的机械性能(包括拉伸强度、弯曲强度、冲击强度和断裂韧性)和固化反应动力学。实验结果表明,杂化树脂的机械性能随HTME-2含量的增加先提高后降低。当HTME-2质量分数为9%时,杂化树脂的冲击强度和断裂韧性分别达到48.25kJ/m2和3.12kPa.m1/2,比纯DGEBA分别提高了177%和53.7%,而且拉伸强度和弯曲强度也有不同程度的提高。利用示差扫描量热仪测试杂化树脂的固化反应过程,通过Coats-Redfern模型确定了固化反应动力学参数,结果显示,HTME-2的加入使杂化树脂的固化反应级数、反应活化能和反应热下降。

Curing Kinetics of Hyperbranched Epoxy/Bisphenol-A Epoxy Hybrid Resin

A novel low-viscosity aromatic hyperbranched epoxy resin(HTME-2)was synthesized by one-step method and was characterized.Mechanical performance,namely tensile strength,flexural strength,impact strength and fracture toughness,and curing kinetics of HTME-2/diglycidyl ether of bisphenol-A(DGEBA)hybrid resin were investigated.Content of HTME-2 in the hybrid resin exhibited important effect on mechanical performance of the hybrid resin.Mechanical performance of HTME-2/DGEBA hybrid resin reached maximum with increasing of HTME-2 content.The impact strength and fracture toughness of the hybrid resin with 9%(mass fraction)of HTME2 were 48.25kJ/m~2 and 3.12kPa·m~(1/2) respectively,which were 2.77 and 1.54 times of corresponding performance of DGEBA.At same time tensile strength and flexural strength could be improved to a certain extent.The curing processes of the hybrid resins were tested by means of differential scanning calorimeter(DSC)at constant heating rate.Kinetics parameters of DGEBA and HTME-2/DGEBA curing systems were obtained by Coats-Redfern model.The reaction order,reaction activation energy and reaction heat lowered with increasing of HTME-2 content in the hybrid resins.