Preparation And Properties Of Flame Retardant Soybean Oil Based Polyurethane Rigid Foam

The research and development of renewable resources has become an important cornerstone of economic development in the new era.Its advantages of large reserves and small pollution are unreachable for fossil energy.In particular,the polyurethane industry produces hundreds of millions of polyurethane products every year,and the output is increasing year by year,but the market is still in short supply,so the use of renewable resources is already the trend.Soybean oil,as a renewable resource,has the advantages of high yield and low price,and is also very conducive to industrialization promotion.In the current domestic and international polyurethane industry,polyurethane rigid foam still occupies an unshakable position,because of its good thermal insulation properties and large specific strength and other characteristics are widely used in refrigerators,freezers,heating pipes and buildings exterior walls.So,the importance of using soybean oil in the polyurethane rigid foam industry is conceivable.In this paper,the use of soybean oil as a raw material,the addition of flame retardant to enhance the fire resistance of the foam,and promote its application in other fields.This paper is divided into three parts: First,two different flame retardants are synthesized by chemical reaction between different reactants.The first flame retardant uses trishydroxymethylphosphine oxide(THPO)and n-butyl glycidyl ether(BGE)as raw materials to synthesize phosphorus-containing flame retardant polyol(THPOB)after 6 hours of reaction under the action of potassium hydroxide;The second flame retardant is synthesized by a two-step reaction,firstly using phenylphosphoryl dichloride(BPOD)and hydroxyethyl acrylate(HEA)under the conditions of triethylamine as an acid scavenger and dichloromethane as a solvent.After reacting for 10 hours at room temperature,the intermediate DABP is obtained,and then the intermediate DABP is reacted with diethanolamine in a molar ratio of 1:2 at a temperature of 30 °C for 48 hours to obtain another phosphorus-nitrogen flame retardant polyol(BPODD).At the same time,a soybean oil-based polyol(DSO)was obtained by reacting epoxidized soybean oil with water under a condition of perchloric acid as a catalyst in an environment of 85 °C for 20 hours.Two different flame retardants and soybean oil based polyol were characterized their by infrared and nuclear magnetic resonance.The second part is to mix different quality THPOB and DSO,the content of THPOB is 0,10%,20%,30%,40% and 50%,respectively.According to the different mass ratio,the polyurethane rigid foam with different properties will be obtained.A series of testing methods were used to investigate the effects of THPOB content,such as limiting oxygen index,vertical combustion,dimensional stability and mechanical properties testing.Finally,it was confirmed that the addition of THPB has a positive effect on the flame retardancy of polyurethane rigid foam,but there is a lack of mechanical properties.At the same time,in the results of dimensional stability test,the linear variation of foam also slightly increased.The third part is to add BPODD to the DSO,the amount of BPODD is 0,10%,20%,30%,40% and 50%,respectively.Different properties of polyurethane rigid foam are obtained according to the mass ratio.A series of testing methods were used to investigate the effects of BPODD content,such as limiting oxygen index,vertical combustion,dimensional stability and mechanical properties testing.Finally,it was confirmed that the flame retardant properties of polyurethane rigid foams were significantly improved after the addition of BPODD;when the amount of BPODD added was small,the mechanical properties were also enhanced.Meanwhile,A small amount of BPODD will also reduce the linear change of the foam.