波聚合制备聚(天然橡胶-接枝-丙烯酰胺)吸水膨胀橡胶

Frontal Polymerization Preparation of Poly(natural rubber-g-acrylamide) for Water-swellable Rubber

采用波聚合工艺快速制备了聚（天然橡胶-接枝-丙烯酰胺）吸水膨胀橡胶.该波聚合过程能够在45℃左右被引发,最高波温达到112℃,波速0.3-1.0 cm·min-1.与传统间歇聚合工艺相比,波聚合制备样品的接枝效率达到51.8%,是传统间歇聚合制品的2.8倍;最大吸水倍率为7.66 g·g-1,是传统聚合制品的1.6倍;聚合时间为传统间歇聚合的1/8.扫描电镜观测发现,波聚合制备的吸水膨胀橡胶呈现均匀分布的蜂窝状微孔结构,孔直径在4-10μm之间,该结构有利于橡胶在保持高强度和弹性的同时,提高吸水性能;而传统间歇聚合制品内则以小于2μm的微孔为主,同时有少数近毫米级的条形大孔存在.

For the first time, a water-swellable rubber, poly （natural rubber-g -acrylamide）, was prepared quickly by frontal polymerization. Compared with batch polymerization, the front polymerization process was studied and the polymers were characterized. The frontal polymerization reaction is ignited after the system temperature is higher than 45 ℃ approximately. As important process parameters, the frontal temperature is about 112 ℃ while the front velocity is between 0.3 cm·min-1 and 1.0 cm·min-1. The grafting efficiency of frontal polymerization is 51.8% which is 2.8 times as much as that of batch polymerization. The maximum water absorption of products prepared via FP was calculated as 7.66 g·g-1 which is 60% higher than that of the batch polymerization. While the reaction time of frontal polymerization is an eighth of the reaction time of batch polymerization. The microstructure of water-swellable rubber synthesized by frontal polymerization was studied. The relatively uniform hollows,at a size range from 4 μm to 10μm,can improve the swelling ability while keep the good strength and elasticity. While the batch polymerization polymers have a lots of holes less than 2μm and sporadic linear holes near 1 mm.