Synthesis And Application Of Oligomeric Polyol Phosphate Flame Retardant

With the increasing usage of rigid polyurethane foam(RPUF)in construction,home furnishing,transportation and other fields,RPUF is invisibly spreading to every corner of people’s lives.However,the extremely flammable nature of RPUF buries a huge hidden danger for the occurrence of fire,and threatens human life and property safety at all times..Therefore,the flame-retardant modification of rigid polyurethane foam cannot be slackened.At present,using reactive flame retardants can avoid some related problems caused by the additive flame retardants which are the deterioration of material properties and nonlasting flame retardancy.Therefore,even if the market share of reactive flame retardants is not high due to the high cost,the complexity of modification process and other reasons,the pace of its research cannot be stopped.Among them,the study of reactive oligomeric phosphoric acid ester flame retardants with larger molecular weight and higher phosphorus content has become a hot spot.In order to achieve the high-efficiency and lasting flame retardancy of RPUF,and also meets the green chemical and environmental requirements,the oligomeric reactive phosphoric acid ester flame retardants prepared with phosphorus pentoxide as phosphorylation reagent has attracted much attention.(1)In this study,phosphorus pentoxide,triethyl phosphate,water and phosphoric acid,propylene epoxide were used as raw materials to prepare oligohydroxypropyl ethyl phosphoric acid ester flame retardant,the effect of dropping temperature of propylene oxide on the properties of the products was investigated,and the reaction conditions of epoxypropane with intermediate were optimized by orthogonal experiment.The amount of propylene oxide,reaction system pressure,reaction temperature and reaction time were optimized to obtain the reaction conditions with the best acid value of the product.The product structure was characterized by FTIR,GPC,and ESI-MS,the thermal stability,physical and chemical properties of the product were analyzed by TGA,chemical titration and etc.(2)In this study,phosphorus pentoxide,trimethyl phosphate,water and phosphoric acid,propylene epoxide were used as raw materials to prepare oligohydroxypropyl methyl phosphoric acid ester flame retardant,the effect of dropping temperature of propylene oxide on the properties of the products was investigated,and the optimal selection of the amount of water,the amount of propylene oxide,the reaction temperature and time through the orthogonal experiment,the reaction conditions with the best acid value of the product are obtained.The product structure was characterized by FTIR,the thermal stability,physical and chemical properties of the product were analyzed by TGA,chemical titration and etc.(3)The synthesis and improvement process of trimethyl phosphate(TMP;the raw material for synthesizing oligomeric hydroxypropyl methyl phosphoric acid ester,i.e.the upstream product)was explored.The molar ratio of raw materials,the dropping temperature of phosphorus oxychloride,the reaction temperature and time were optimized by orthogonal experiment,a colorless and transparent TMP product with a yield of 95.1% and an acid value of less than 0.1 mg KOH/g was obtained.Methanol was recovered and applied,we also shortened the esterification reaction time and improved the cumbersome process of the posttreatment process.(4)The synthetic oligomeric hydroxypropyl ethyl phosphoric acid ester was used to prepare flame-retardant polyurethane rigid foam by one-step foaming method,the flame retardancy,thermal stability and mechanical properties of the flame-retardant RPUF were tested.