High stretching tuned GO decorated non-shrinkable polyacrylic acid-based composite fiber and its excellent performance as a Fenton catalyst

Abstract

Mixed valent iron ions were used to create a flexible ionic crosslinking network through coordination, making PAA fiber highly stretchable, and the fiber was highly stretched to tear graphene oxide (GO) sheets into discontinuously-dispersed monolayer sheets. The monolayer sheets could construct many hydrogen bonds with PAA chains to serve as knots to hinder chain movement, controlling the shrinkage of stretched fiber. Co-solvent formamide could improve the heat resistance of PAA fiber through special calorific effect; thus the highly-stretched fiber could tolerate high temperature heat setting. Due to the advanced structure induced by stretching, internal force relaxation caused by heat setting, and the existence of knots, the resulting fiber possessed the features of high strength and no shrinkage. High strength made the fiber mechanically applicable, and the unshrinkability could help it to maintain large specific surface area and strong iron ions-immobilizing capability. As a result, the catalytic activity of non-shrinkable fiber was increased by 25% compared with that of shrinkable fiber for methylene blue (MB) decolorization, and iron ion loading ratio was increased by 174.5%; however, iron ion leaching ratio was decreased by 76.5%, which was conducive to reusability improvement. Thereby, the resulting fiber could be repeatedly used to decolorize MB.