腐植酸钠/聚丙烯酰胺/粘土杂化水凝胶的研究

STUDIES ON SODIUM HUMATE/POLYACRYLAMIDE/CLAY HYBRID HYDROGELS

以过硫酸钾为引发剂、N,N′-亚甲基双丙烯酰胺为交联剂、丙烯酰胺单体和腐植酸钠、Laponite RD粘土为原料,用溶液聚合交联法合成了腐植酸钠/聚丙烯酰胺/粘土(SH-PAM-Clay)系列水凝胶.用场发射扫描电镜对其表面形貌进行了研究,并对水凝胶的吸水性和流变性能进行了测试和研究.结果表明这系列水凝胶都具有致密的网络结构和优良的吸水性能.

A series of sodium humate/polyacrylamide/clay （SH-PAM-Clay） hydrogels was synthesized by solution polymerization and crosslinked using acrylamide, sodium humate （SH） and clay Laponite RD as raw materials, potassium persulfate （KPS） as the initiator and N, N′-methylenebisacrylamide （MBA） as the cross-linking agent. The morphology of the hydrogels was characterized by field emission scanning electron microscope （FESEM）, and their rheological and water-absorption properties were also examined. Experiments showed that SH/PAM/Clay hydrogels have homogeneous network structures and high water-absorbent properties. Swelling experiments show that the swelling rate decreases with the increase of SH content, and the introduction the hydrophilic clay improves the water absorbency properties of SH/PAM/clay hydrogel systems. Relaxation of polymer chains of the hydrogels controls the swelling process. Rheological experiments show that the elastic response of the hydrogel system is stronger than the viscous response. Chemical cross-link due to chemical cross-linker and physical cross-link due to weak interactions coexist in the hydrogel network. The interactions between SH and polymer chains are very weak, and SH acts as lubricant. While the contents of clay in the hydrogels play an important role in affecting rheological properties of the hydrogel system. The Han plot proves that clay and SH are compatible with PAM, and SH/PAM/clay hydrogels are homogeneous.