纳米SiO_2接枝聚合改性及在EVOH中的应用

Graft Polymerization Modification and Application of Nano-SiO_2

以硅烷偶联剂3-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH570)对纳米二氧化硅(SiO_2)进行表面处理,通过分散聚合工艺分别制得SiO_2-g-KH570-g-PS、SiO_2-g-KH570-g-PMMA和SiO_2-g-KH570-g-PAN,采用熔融共混法制备了乙烯-乙烯醇共聚物(EVOH)/纳米SiO_2复合材料(5%(质量分数,下同)SiO_2),并吹塑薄膜。利用傅立叶红外(FT-IR)、透射电镜(TEM)、扫描电镜(SEM)对纳米SiO_2和复合材料进行表征,并测试了复合材料的性能。结果表明,纳米SiO_2与偶联剂KH570形成化学键合,与聚苯乙烯(PS)、聚甲基丙烯酸甲酯(PMMA)、聚丙烯腈(PAN)已接枝聚合。由于纳米SiO_2接枝聚合物后在EVOH中的分散性改善和界面相互作用力提高,因此复合膜的性能明显提高,相较于EVOH/纳米SiO_2(表面未处理)复合材料(5%SiO_2),拉伸强度提高21.8%,透湿、透氧系数分别下降12.3%、19%,透光率达到75.8%,雾度为13.65%。

Nanosilica （ nano-SiO2 ）, modified by 3-trimethoxysilyl-propyl-methacrylate （KH570）, was used to prepare SiO2-g -KH570-g-PSt, SiO2-g-KH570-g-PMMA and SiO2-g-KH570-g-PAN by dispersion polymerization process. The modified nano-SiO2 was used to prepare the ethylene-vinyl alcohol copolyrner （EVOH）/nano-SiO2 composites, and the composites were blown to film. The nano-SiO2 and composites were characterized by Fourier- transform infrared（FT-IR）, transmission electron microscope（TEM） and scanning electron microscope （SEM） and the properties of composites were tested. The results show that： chemical bonds are formed between nano-SiO2 and KH570, and graft polymerization is occurred between polystyrene （PS）, polymethyl methacrylate （PMMA）, polyacrylonitrile（PAN） and nano-SiO2. The properties of films which were prepared by the nano-SiO2 grafted with polymers have been improved greatly. In contrast to the EVOH/SiO2 composites prepared with unmodified SIO2（5 % SiO2）, the tensile strength of the EVOH/SiO2 composites prepared with modified nano-SiO2 increases by 21.8%, and the moisture permeance factor and the oxygen permeability coefficient of those decreases by 12.3 % and 19 % respectively. The transmittance is 75.8 % and the haze is 13.65 %.