Study On Hydrophilic Copolyacrylonitrile Fibers

Copolyacrylonitrile particle was obtained by water-deposit polymerization, using acrylonitrile(AN), vinyl acetate(VAc), potential crosslinker(HQ) as monomer, NaClO3 as initiator at some temperature. It was then dissolved in N,N-dimethylacetamide(DMF), spun by wet spinning method to get Copolyacrylonitrile(CPAN) fiber and CPAN/cellulose acetate(CA) blend fiber. Under proper crosslinking and hydrolyzing conditions, two new kinds of fiber with good water absorbency and good water retention were prepared. Nonwovens with CPAN fibers and CPAN/CA fiber were prepared by needle punching respectively.When NaClO₃ was controlled to be 0.5wt% of monomer , the monomer amount was controlled to be about 23wt%, the pH was controlled about 2 and the polymerization temperature was about 45 ℃ for 1.5h, the copolyacrylonitrile which contained 2-hydropropyl acrylate (HQ) had good ability to dissolve and spin. Using 40wt% DMAc solution as coagulation bath, CPAN fibers with good properties were got under room temperature. After heat-treated in boiling water bath, the inner stress in CPAN fibers was relaxed and the fibers showed good size stability during post-crosslinking.The effects of crosslinking conditions and hydrolyzing conditions were investigated. The crosslink reaction carried out perfectly on the fibers with 10wt% HQ at 180℃ for 30min. the CPAN fiber hydrolyzed in 10% NaOH solution at 80℃ for 10min, not only had good water absorbency(5g/g), but also can keep originally mechanics capability. The needle punched nonwovens obtained using these CPAN fibers had the water retention more than 80wt% in this research.The interphase separation in the mixture with CPAN and CA was investigated. The CPAN/CA blend fiber would produce a lot of finestras which would accelerate the saponification reaction and enhance the water absorbency.The influences of the post-crosslinking conditions and hydrolyzing processes on the chemical structure of the fiber, the surface structure of the fiber, assembling state of the moleculars in the fiber and the mechanic properties of the fiber were also discussed using FTIR, SEM, TGA, DSC and DMA.