Abstract: Polyvinyl alcohol (PVA) is a bio-degradable polymer material. Using PVA as fiber forming agent, after being dissolved in water, it is mixed with halogen-free (containing phosphorus and nitrogen) flame-retardant agent tetrakis (hydroxymethyl) phosphonium chloride (THPC) and urea to form a mixed solution; after filtration and deaeration, the solution goes through wet-spinning, drying, heat stretching (in-situ crosslinking reaction), washing, heat-setting and hydroformylation processes to prepare a flameretardant PVA fiber with cross-linked network structure. The study results show that the prepared PVA fiber has good flame-retardant and mechanical properties and its limiting oxygen index (LOI) is up to more than 29%.

Key words: PVA fiber; cross-linked network structure; flame-retardant; mechanical property; limiting oxygen index (LOI)