| On the basis of the analysis of the characteristic and mechanism, type and preparation method, research and application development of superabsrobent fibers, acryle acid (AA) and acrylamide (AM) were chosen as monomers because of the hydrophilic side group on their molecules. 2-hydropropyl acrylate (HQ) was used as potential crosslinking agent due to its activating hydroxyl group and its unsaturated bond. Copoly (acrylic acid-acrylamide) (PAAM) was prepared by aqueous solution polymerization, and CPAAM fibers with three- dimensional network structure were prepared by heat treatment after spinning of PAAM aqueous solution. Sepiolite-filled CPAAM (CPAAMx) fibers, PVA-CPAAM blend fibers and aliphatic alcohols modified CPAAM fibers were made by introducing sepiolite, PVA and aliphatic alcohols into CPAAM fibers, respectively. The factors, on which the structures and properties of the fibers depended, the rheology of PAAM aqeous solution and sepiolite-filled PAAM suspension, the mechnism of crosslinking and the effect of three-dimensional network structure on the water absorptive properties of fibers were studied.The effect of potential crosslinking agent type and content, crosslinking temperature and time on the water absorptive property of CPAAM was firstly studied. The results showed that per gram CPAAM, which was prepared by chosing HQ as a potential crosslinking agent with content of lwt% and heat crosslinking at 140°C for 30 minutes, could absorb 400 g distilled water or 60 g 0.9% NaCl solution.The effect of polymerizing conditions on the copolymerization kinetics and the dependence of water absorptive properties of PAAMx on its sepio-lite content and crosslinking condition were studied. The optimal polymerizing conditions in this research were: initiator content of 0.5wt%, AA neutralization of 60% and sepiolite content of 5wt%. The optimal crosslinking conditions in this research were crosslinking for 30min at 140℃.The rheology of PAAM aqueous solution and sepiolite-filled PAAM suspension was investigated. The decrease of shear viscosity with increasingshear rate showed the shear shinning. Lower average viscosity molecular weight and higher temperature would lead to a lower shear viscosity of PAAM aqueous solution. The shear viscosity of sepiolite-filled PAAM suspension decreased with the increase in sepiolite content and its concentration.The study of CPAAMx fiber showed the complementary of the organic phase and inorganic phase in the fiber. The results indicated that, the gel fraction, thermal stability, tensile strength and water absorptive property of the fiber were developed by filling some sepiolite in the fiber. Fiber which contained 3wt% sepiolite obtained higher water absorbency with the water retention of more than 80%.The study of PVA-CPAAM blend fiber showed the changing of congery states of both PVA and PAAM molecules after mixing. Chemical crosslink points between PAAM molecules were formed after heat-treatment, and the water absorbency of fibers decreased with the increase in crosslinking temperature and time. Tensile properties of PVA-CPAAM blend fibers were also studied. The results showed that PVA-CPAAM blend fibers could be used for nonwoven manufacture.The dependence of modifying effective and water absorptive properties of aliphatic alcohols modified fibers on alkyl chain length of aliphatic alcohols and volume ratio of isopropyl alcohol to water (Hmix) in the modified mixture was studied. Incipiently, the modified fibers with longer alkyl chain had higher modifying effective. With the increase in modifying time, the modifing effective of fibers with shorter alkyl chain increased quickly. In this research, the fibers modified by 1-butanol mixture for 1 ~ 6 min with Hmix of 1/1 obtained better water absorptive properties.
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