Acrylic Acid - Acrylamide Copolymer / Poly (vinyl Alcohol) Blend Fibers

Fibers based on poly(acrylic-co-acrylamide)(CAA) and Poly(vinyl alcohol)(PVA) blends were prepared using N-hydroxymethyl acrylamide as a post-crosslinking agent. The blend aqueous solution was extruded into an acetone coagulation bath to form continuous CAA/PVA (CAMP) gel fibers via a wet-spinning method. The CAMP gel fibers were dehydrated by exchanging water with acetone, thermal-crosslinked. The CAMP fiber has large water absorbency and good water retention capacity.The influence of the synthetic variables and post-crosslinking process on water-absorbency of the CAMP fibers were studied in this paper, the results showed that the optimal synthetic conditions were as follows: the initiator concentration, 0.4wt% of the monomer concentration; degree of neutralization of acrylic acid, 85%; the amount of acrylamide and poly(vinyl alcohol) in the blends, 20% and 20% respectively; and the post-crosslinking agent content, 0.5%. The absorbability of the fibers post-crosslinked at 120℃ for 4 minutes to distilled water and 0.9% NaCl solution was 360 g/g and 40 g/g respectively. The CAMP fibers had good water retention capability and heat water stability. Higher the post-crosslinking temperature was, the better regularity of the cluster structure of the fibers.The CAMP aqueous solution wet-spinning process was researched. The results showed, as a spinning solution, the optimal concentration and neutralization of the CAMP aqueous solution was 25% and 85% respectively. The solution had good fluidity, spinnability, dynamic stability, and would never be demixing. The original CAMP fibers had better water absorbability when the spinning temperature was 80℃ and pressure was 0.4MPa.Structures of the CAMP fibers were also discussed. The results showed that the hydrogen bonding between the PVA and CAA damaged the regularity of crystalline field and the crystallinity of the fibers reduced. The cluster structures of each phase in the blend were changed and movement of the molecular chain segment was reduced.The studies on the influence of stretching process on the appearance andmechanical performances of CAMP fibers showed, that orientation of the molecular along the axis of the fiber was improved after stretching in the steam bath, and the mechanical performance were also improved.