氟代烷氧基聚磷腈弹性体的合成及性能研究

Preparation of poly(fluoroalkoxyphosphazene)elastomer and its performances

通过聚二氯磷腈(PDCP)与2,2,2-三氟乙醇钠、2,2,3,3,4,4,5,5-八氟戊醇钠(1∶1)和少量烯烃钠盐的亲核取代反应,制得可交联型的氟代烷氧基聚磷腈(e-PTOFP)。通过核磁共振(31P NMR,~1H NMR)测试,对其结构进行了表征。采用无转子硫化仪、氧指数实验(LOI)、垂直燃烧实验(UL-94)、烟密度测试仪和热失重(TGA)对氟代烷氧基聚磷腈弹性体的硫化性能、燃烧性能和热稳定性进行了分析。通过红外光谱(FTIR)对其热解残留物的结构进行了研究。结果表明,少量不饱和侧基的引入赋予了氟代烷氧基聚磷腈硫化性能,硫化后弹性体的氧指数为54.5,垂直燃烧等级为V-0,烟密度等级(SDR)为21.93,具有优异的阻燃性能、低烟性能和热稳性能,且其热降解的残留物主要是含P=O,N—H的磷氮化合物。可看出氟代烷氧基聚磷腈弹性体是潜在的综合性能优良的绝热层材料。

Poly（fluoroalkoxyphosphazene） elastomers containing olefin groups（e-PTOFP） was synthesized by nucleophilic substitution of the chlorine atoms of Poly（dichlorophosphazene）（PDCP） with respective sodium salts,and chemical structure of elastomers were characterized by31 P NMR,~1H NMR.The properties of vulcanization,flame retardant and thermal stability of the polymers were characterized by the no-rotor rheometer,limited oxygen index（LOI）,UL-94 test and thermogravimetric analysis（TGA）respectively.Results show that flame retardant property reaches V-0 grade of UL-94 level,54.5 of LOI values,as well as smoke density grade of 21.93.The pyrolytic residues of e-PTOFP were characterized by Fourier Transform Infrared（FT-IR）.The incorporation of trace amounts of cross-linkable olefin can not only present poly（fluoroalkoxyphosphazene） with vulcanizable properties but also significantly enhance its thermal stability,and higher yields of residues,which mainly contain P=O,N—H of phosphorus compounds and nitride.The fluorinated alkoxy polyphosphazene elastomers meet needs of insulation matrix for many potential advanced rocket applications.