基于乙基纤维素-马来海松酸酯的酸酐类环氧固化剂的固化及性能研究

Curing Kinetics and Properties of Anhydride Epoxy Curing Agent Based on Ethyl Cellulose-maleopimaric Acid Ester

通过酯化反应将马来海松酸(MPA)接枝到乙基纤维素(EC)分子侧链,合成乙基纤维素马来海松酸酯(EC-g-MPA),并将EC-g-MPA作为高分子酸酐类环氧树脂固化剂,与环氧树脂(ER)进行固化反应制备了一系列的环氧树脂(EC-g-MPA/ER)聚合物。采用红外光谱对固化后的环氧树脂的化学结构进行了表征,非等温DSC对固化体系的固化动力学进行了研究,结果表明:固化后环氧树脂中归属于酸酐的红外特征吸收峰完全消失随着升温速率的增加固化速率逐渐增加,固化度逐渐降低。该固化体系的活化能(Ea)为73.94 kJ/mol,该固化体系的指前因子(A)为1.27×10^6s^-1,反应级数(n)为0.9,表明该固化反应是一个复杂的过程。热力学性能研究表明:随着固化剂含量的增加,产物的玻璃化转变温度逐渐升高,且固化后的树脂具有优异的热稳定性。机械性能研究表明:随着固化剂EC-g-MPA含量的增加,固化产物的机械强度逐渐增加,可以通过调整固化剂含量制备具有不同机械性能的环氧聚合物。

The ethyl cellulose maleopimaric acid ester(EC-g-MPA)was synthesized by grafting maleopimaric acid(MPA)onto the cellulose backbone(EC).Then,a series of epoxy resin polymers(EC-g-MPA/ER)were prepared via curing reaction between EC-g-MPA,acting as acid anhydride epoxy resin curing agent,and epoxy resin(ER).FT-IR was carried out to confirm the chemical structure of the products.And non-isothermal DSC was carried out to investigate the curing kinetics of the curing system.The results showed that the FT-IR characteristic absorption peak attributed to anhydride disappeared completely after curing.The activation energy of the curing system was 73.94 kJ/mol,the pre-factor(A)of the curing system was 1.27×10^6 s^-1,and the reaction order(n)was 0.9,indicating the curing reaction was a complex process.The thermodynamic performance study showed that the glass transition temperature of the product gradually increased with the increase of EC-g-MPA content,and the cured resin also showed excellent thermal stability.Mechanical properties study showed that the mechanical strength of the cured product increased with the increase of EC-g-MPA content,and the epoxy resins with different mechanical properties could be prepared by tuning the content of the curing agent.