Study On Synthesis And Properties Of Temporarily Water-soluble Hydroxyl-containing Phosphonate Flame Retardant

Organophosphorus flame retardants are the flame retardants which are the most well-studied class among all flame retardants.This paper proposes to synthesize a new type of hydroxyl-containing phosphorus flame retardant,because the hydroxyl-containing viscose needs to be reacted to form a yellow solution of cellulose xanthate,and then filaments are obtained in an acidic coagulation bath.In this experiment,it is envisaged that the synthesized hydroxyl-containing flame retardant can also undergo a yellowing reaction and dissolve in water,and then precipitate out of the acid solution,and the flame retardant performance of the flame retardant does not change.It can reacted with viscose at the same time,and precipitate at the same time.Thereby replacing sanding,to achieve the purpose of combining the flame retardant with the viscose fiber molecule and molecule,thereby improving the flame retardant performance.Sandoflame5060 flame retardant has good flame retardant properties,and it is envisaged to synthesize a flame retardant containing phosphorus in this experiment.Therefore,based on the characteristic of hydroxyl and the excellent flame retardant properties of phosphorus element,a new type of phosphonate-based flame retardant containing hydroxyl group was designed and synthesized.In this paper,14 hydroxyl-containing thiophosphonates were synthesized with polyols and thiophosphate chloride,which is composed by neopentyl glycol and thiophosphorous trichloride;5 new hydroxyl-containing phosphonate were synthesized using pentaerythritol,neopentyl glycol,phosphorus trichloride,and formic acid.Hydroxyl-containing thiophosphonate can react with carbon disulfide to generate corresponding xanthate in alkaline conditions and dissolve in water.Then it will precipitate with viscose fiber in acid bath to realize the mixing at the molecular level.The flame retardancy test shown that selected title compounds have a certain flame retardancy for viscose fiber.In order to study the flame retardancy in viscose fiber of above,compound 9 and 13 was selected to detect the flame retardancy based on the content of phosphorus and sulfur and melting point.Compound9(484.42 g,69%)and compound 13(471.60 g,66%)was got with large scale synthesis.27.0% of LOI can be reached with content of 20% FR 9 in viscose fibre,for FR 13,the content of 25%(27.0% of LOI).The flame retardancy of FR 9 is better than that of FR 13 because of higher content of phosphorus and sulfur.