SYNTHESIS OF SULFUR-CONTAINING NITROGEN AND PHOSPHORUS FLAME RETARDANT AND ITS APPLICATION TO POLYACRYLONITRILE FIBER

Hao Feng-Ling, Song Chuan-Jie, Liu Qun

ABSTRACT:Flame retardant ditrimethylolpropane diphosphothiourea (DDT) was synthesized by using ditrimethylolpropane(DTMP), phosphoryl chloride(POCl3) and thiourea as raw materials. Preparation of finishing agent with ethanol as solvent and used as a flame retardtant for polyacrylonitrile fiber. The effect of finishing agent solution concentration, curing temperature and curing time on flame retardancy, whiteness and breaking strength of polyacrylonitrile fiber was also discussed. The optimal synthesis conditions for DDT were determined: the finishing liquid concentration was 200g/L and baking 80℃ for 3 min. The results showed that the flame-retardant efficiency reached national standard B1 level and retained higher breaking strength and whiteness.

Keywords:Thiourea, flame retardant, polyacrylonitrile fiber, synthesis process.