纳米SiO_2包覆硼酸锌及其原位聚合PET的阻燃性能

Nano silica encapsulated zinc borate and the fire-retardant property of PET synthesized by in-situ polymerization

在乙醇/水体系中,采用溶胶-凝胶法在硼酸锌(ZB)表面包覆纳米SiO_2对其进行改性,利用扫描电镜(SEM)和透射电镜(TEM)研究了H_2O/TEOS的摩尔比对SiO_2粒子大小及包覆效果的影响。然后利用原位共聚法制备出阻燃聚酯,研究了包覆后的硼酸锌对聚酯缩聚过程及阻燃性能的影响。结果表明:当体系原料H_2O/NH_3/TEOS的摩尔比为7.1:3.3:1时,SiO_2可以在硼酸锌表面形成致密的保护层,成功抑制了Zn离子对聚酯缩聚过程的催化效应。将包覆后的硼酸锌与阻燃剂2-羧乙基苯基次膦酸的乙二醇酯化液(CEPPA-EG)一起加入到聚酯聚合中,能发挥很好的协同作用,聚酯的阻燃性能得到明显提高,极限氧指数(LOI)值由22提高到35,UL-94等级由V-2级提高到V-0级,炭层石墨化程度明显增高。

In this article,the modification of zinc borate encapsulated by nano silica in ethanol/water system through sol-gel method was studied.SEM and TEM were used to research the influences of the molar ratio of water/TEOS on the particle size of silica and the covering effect.Then the flame retardant polyester was prepared by in-situ copolymerization.And the effects of coated zinc borate on the polycondensation process and fire retardant effects of polyester were studied.The results showed that the dense protective layer made up of SiO2 could be formed on the surface of zinc borate when H_2O/NH_3/TEOS molar ratio was 7.1：3.3：1.The catalytic effect of zinc-ion on the polycondensation process of polyester was suppressed successfully.A good cooperation effect could be made when the coated zinc borate and CEPPA-EG which had been pre-synthesized from 2-carboxyl ethyl（phenyl） phosphinic acid（CEPPA） and ethylene glycol（EG） were put into the polycondensation process of polyester.The flame resistant properties of polyester were markedly improved.The LOI value of polyester was increased from 22 to 35 and the UL-94 level was increased from V-2 to V-0.The degree of graphitization of polyester was also increased significantly.