膨润土/丙烯酰胺接枝改性天然橡胶制备吸水膨胀橡胶

Preparation and Characterization of Water Swelling Rubber by Bentonite/Acrylamide Grafted and Modified Natural Rubber

实验以过硫酸钾(KPS)/亚硫酸氢钠(SHS)为氧化还原引发体系,采用化学接枝的方法改性天然胶乳,合成出天然橡胶与丙烯酰胺接枝共聚物NR-g-PAM,并在反应过程中加入无机膨润土(BT),制备一种吸水膨胀天然橡胶(WSNR)。探究单体配比、引发剂用量对接枝反应的影响,膨润土用量对WSNR吸水率、吸水速率、重复吸水率的影响,并对WSNR保水性、耐矿化盐水能力及热失重过程进行分析。结果表明,吸水单体与天然橡胶的质量比为0.8,引发剂用量为单体质量分数的0.75%时接枝率及接枝效率最高。膨润土均匀分布于WSNR网络骨架中,吸水速率随膨润土用量增加而减慢,耐矿化盐水能力提高;重复吸水率及保水性均优异于未添加膨润土的WSNR,膨润土的加入使WSNR在较高温度下才会蒸发失水,自由水含量减少,结合水含量增多。

A new type water swelling natural rubber（WSNR）was prepared with natural rubber modified by acrylamide grafting in KPS/SHS oxidation-reduction system.Bentonite as an inorganic material was added in this reaction system.Effects of monomer ratio and initiator dosage on the grafting reaction were discussed.Water absorption ratio and repeat water absorption ratio of WSNR were measured.Thermogravimetric process of WSNR was analyzed.Experimental results indicate that grafting ratio and grafting efficiency are the highest when the monomer to natural rubber mass ratio is 0.8and the initiator is 0.75% of the monomer mass fraction.Water absorption rate is slow when bentonite exists.The capacity of salt resisting keeps increasing.Repeat water absorption ratio and water-retaining property are better than those without bentonite.With the addition of bentonite the free water content decreases and bound water content increases.Under hot circumstance the capacity of water loss keeps well.