AMPS对环氧树脂改性的研究

Study on Waterborne Epoxy Resin Modified by AMPS

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)对环氧树脂进行改性,制备的改性环氧树脂不用中和即可在水中分散形成稳定的乳液。研究发现AMPS与环氧树脂原料摩尔比为1∶0.75时,制备的改性树脂水分散乳液的粒径最小、粒径分布最窄。讨论了反应时间对改性产物特性粘数、反应体系的酸值、制备的乳液的粒径及粒径分布的影响。由红外光谱表征,AMPS-EP共聚物中保存了环氧树脂的环氧基,同时引入了亲水性的磺酸基。由DSC分析,AMPS-EP的玻璃化转变温度为140℃,高于原料AMPS均聚物与环氧树脂。实验结果表明了AMPS与环氧树脂的主要反应为:在自由基引发剂的作用下,环氧树脂主链上产生的链自由基,引发AMPS的丙烯酰胺基接枝反应,以及AMPS的磺酸基与环氧树脂的环氧基的酯化反应,及由此产生的环氧树脂的扩链反应。

Epoxy resin （EP） can be stably dispersed in water without neutralization after modified with 2-acrylamido-2-methyl-1- propanesulfonic acid （AMPS）. It is found that particle size and particle size distribution of AMPS-EP would be smallest and narrowest, respectively, when the mole ratio of AMPS to EP is 1：0.75. The influences of modification reaction time on intrinsic viscosity [η], acidity, particle size and particle size distribution were discussed. IR spectrum indicates that the epoxy group is retained and hydrophilic sulfonic group is introduced into the copolymer AMPS-EP. DSC analysis shows that glass transition temperature of AMPS-EP reached 140℃ which is higher than that of beth EP and homopolymerized AMPS. It is clear from the results that the mechanism of the modification reaction could be described as follows： EP backbone chain becomes chain radical after heating decomposition of initiator, which result in the grafting reaction with acrylamido group of AMPS; besides, esterification of sulfonic group in AMPS with epoxy group in EP favors to chain extension of EP.