To improve the flame resistance of polyvinyl alcohol (PVA) fibers, the well-designed permanent flame-retardant coatings were introduced on the surface of PVA fibers. Acrylonitrile (AN) was firstly grafted on the PVA fiber surface and then the grafted fibers (PVA-g-AN fibers) were reacted with hydrazine hydrate and copper sulfate solution to form the coatings with flame retardant performance. The structure of the fibers was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The flame-retardant performance of the fibers was evaluated by limiting oxygen index (LOI) and micro calorimeter (MCC) tests. It was found that the coatings were effective in improving the flame resistance of PVA fibers. SEM photos of char residues and the results of the TG-IR technique revealed that flame retardance is mainly provided through the barrier action of the coatings with the partial effect of gaseous phase.
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