甲基取代二芳基氧化膦阻燃改性环氧树脂的研究

Study on Methyl Substitued Diarylphosphine Oxide Flame Retardant Modified Epoxy Resin

通过苯基二氯化膦(DCPP)分别与甲苯和间二甲苯反应,制备了(4-甲苯基)苯基氧化磷(4-MPO)和(2,4-二甲苯基)苯基氧化磷(2,4-DMPO)两种新化合物。以目标化合物为反应型阻燃剂合成了双酚A型含磷环氧,并进一步制备了4,4′-二氨基二苯砜固化的阻燃环氧树脂。分别测试阻燃环氧树脂的热稳定性、阻燃性、吸水性、介电性能,并研究了阻燃机理。结果表明:两种阻燃剂均能提高环氧树脂的阻燃性,其中2,4-DMPO阻燃EP的效率更高。4-MPO改性环氧树脂的磷含量为0.9%(质量分数,下同)时,其极限氧指数(LOI)达到31.5%并通过UL-94 V-0等级,2,4-DMPO改性环氧树脂的磷含量为0.6%时,其极限氧指数(LOI)达到30.3%并通过UL-94 V-0等级。与未改性环氧树脂相比,4-MPO和2,4-DMPO改性环氧树脂的热稳定性、T_(g)和吸水性都有所下降,但介电性能明显提高,2,4-DMPO改性环氧树脂表现出更高的阻燃性和更好的介电性能。阻燃机理研究表明,两个阻燃剂均通过气相和固相阻燃机理发挥作用,并以气相机理为主。以上结果表明,两种化合物均可作为环氧树脂的良好阻燃剂。

Two new compounds,(4-methylphenyl)phenylphosphine oxide(4-MPO)and(2,4-dimethylphenyl)phenylphosphine oxide(2,4-DMPO)were synthesized by the reaction of phenylphosphorus dichloride(DCPP)with toluene and meta-xylene,respectively.The target compounds were introduced as reactive flame retardants into bisphenol A epoxy resin to prepare phosphorus-containing epoxy and flame retardant epoxy resin cured by 4,4′-diaminodiphenylsulfone was further prepared.Thermal stability,flame retardancy,water absorptivity and dielectric property of the flame retardant epoxy resin were tested,and the flame retardant mechanism was studied.It was found that the two flame retardants can effectively improve the flame retardancy of epoxy resin,the 2,4-DMPO exhibits higher flame retardant efficiency.The resulting flame retar-dant EP achieved a LOI of 31.5%and a UL-94 V-0 rating when the 4-MPO modified epoxy resin phosphorus content was 0.9%(mass fraction,the same below),while the flame retardant EP demonstrated a LOI of 30.3%and received a UL-94 V-0 rating when the phosphorus content of the 2,4-DMPO modified epoxy resin was 0.6%.Compared with unmodified epoxy,the thermal stability,T_(g) and water absorptivity were slightly decreased,but the dielectric property was significantly improved.2,4-DMPO modified epoxy resin showed higher flame retardancy and better dielectric property.The two flame retardants both act through gas phase and solid phase flame retardant mechanism,and the gas phase mechanism plays an important role.