丙烯酸酯改性胺固化剂对环氧树脂防火涂料玻璃化转变温度及性能的调控

Regulation of Acrylate Modified Amine Curing Agent on Glass Transition Temperature and Properties of Epoxy Fire Retardant Coatings

文中利用Michael加成反应得到了不同碳链长度的丙烯酸酯改性三乙烯四胺固化剂,并将其用于制备环氧树脂基膨胀防火涂料。采用核磁共振氢谱对所得改性固化剂进行了表征;差示扫描量热分析证明,将不同碳链长度的丙烯酸酯结构引入固化剂分子中可以有效对环氧树脂交联体系的玻璃化转变温度进行调节(玻璃化转变温度在41.4~101.5℃之间变化);采用热失重分析和极限耐火测试对防火涂料的防火效果进行了测试;采用扫描电镜对耐火测试后炭层的微观形貌进行了分析。结果表明,涂料的防火性能与固化剂的种类即固化体系的玻璃化转变温度密切相关,当采用丙烯酸十二烷基酯改性三乙烯四胺为固化剂时,固化环氧树脂的玻璃化转变温度为87.6℃,其防火涂料的极限耐火时间最长,达到43.2min,膨胀倍率为12,拥有致密、连续的炭层结构,其平均孔径为1.75μm。同时,丙烯酸酯改性三乙烯四胺制备的环氧漆膜的耐紫外老化性能和韧性都得到了提高。

Curing agents of triethylene tetramine modified by acrylate with various carbon chain length were prepared by Michael addition reaction,which were used to prepare epoxy resin-based intumescent fire retardant coating.The structure of the prepared curing agents was characterized by 1 H-NMR.DSC analysis results reveal that the glass transition temperatures(Tg)of the epoxy thermosets can be adjusted by the curing agents modified by acrylate with various carbon chain lengths.The Tg varies in the range of 41.4~101.5℃.TGA and fire endurance tests were used to investigate the fire performance of the prepared coatings.SEM tests were carried out to record the microstructure of the carbon layer after combustion.The results show that the fire performance of prepared coating is closely related with the structure of the curing agent i.e.the Tg of the epoxy thermosets.As triethylenetetramine modified with dodecyl acrylate was used as curing agent,the glass transition temperature of the epoxy thermoset is 87.6℃,and the fire resistance time of its fire retardant coating can reach 43.2 min with a expansion ratio of 12:1.The carbon layer after combustion is dense and continuous with an average pore diameter of 1.75μm.The UV aging resistance and toughness of the epoxy coating film prepared by the flexible acrylate modified curing agent are improved as well.