Effect of degree of saponification on structural and property change of poly(Vinyl alcohol) fibers

To improve the drawability and finally the mechanical properties, poly(vinyl alcohol)s (PVA 86 , PVA 93 , and PVA 99 ) with respective degrees of saponification of 86, 93, and 99% were synthesized using solution polymerization. Following the synthesis dimethylsulfoxide (DMSO) solutions of the PVAs were gel‐spun into methanol. After extraction of DMSO from the as‐spun fibers the dried fibers were first drawn at 120 °C then at 180 °C. An analysis of the structure and properties of the fibers was performed using FT‐IR, differential scanning calorimetry (DSC) and a fiber strength tester. The degree of saponification had an effect on the formation and intensity of the intermolecular hydrogen bonds, melting, drawability and strength of the PVA fibers. Low degrees of saponification weakened the intermolecular hydrogen bonds and interfered with the formation of crystallites, causing low melting points and low heat of fusion. Generally, drawing was easier to carry out at lower temperature, and higher draw ratios could be obtained, leading to higher fiber strengths.