不同性能的双亲性纳米TiO_2复合粒子改性聚偏氟乙烯超滤膜结构与性能的研究

Study on the influence of different property of amphiphilic nano-sized TiO_2 composite particles on structure and properties of PVDF ultrafiltraton(UF) membrane

利用无皂乳液聚合法合成双亲性聚丙烯酸(PAA-)g-聚甲基丙烯酸甲酯(PMMA)-g-硅烷偶联剂KH570-g-纳米TiO2复合体,通过调节亲水链中丙烯酸(AA)与甲基丙烯酸甲酯(MAA)单体的比例控制复合粒子的表面性能。利用红外光谱、接触角测定、扫描电镜(SEM)等表征技术研究不同表面性能的双亲性纳米TiO2复合粒子对聚偏氟乙烯(PVDF)超滤膜结构与性能的影响。研究表明,随着亲水链中AA单体含量增多,复合体亲水性增强,改性膜亲水效果越显著,膜通量越大,但易形成大孔,截留率低,且改性膜压密性欠佳。而复合体亲水链中MMA单体含量越多,膜亲水改性效果越差,膜通量低,但膜压密性能好。两种单体最佳比例应控制在40%～60%,此时改性PVDF复合超滤膜性能优异,膜通量、截留率分别达到80mL/cm2.h和80%以上。

The amphiphilic PAA-gaft-PMMA-gaft-silane coupling agent KH570-gaft-nano-sized TiO2 composite particles was synthesized via to the method of non-soap emulsion polymerization,and through adjusting the rate of AA and MMA to control the surface properties of composite particles.The influence of nano-sized TiO2 composite particles with different surface properties on the structure and properties of PVDF UF membranes had been studied through the characterization of FTIR,contact angle,SEM and membrane permeation test the results showed that the hydrophilic of complex enhanced,the hydrophilic of modification membrane gained well effect,and the flux was with the content of acrylic acid（AA） was increasing in the hydrophilic chain.But it was easy to form a hole and decrease the retention rate and the compaction property of modification membrane.While for the increasing content of methyl methacrylate（MMA） in the hydrophilic chain,the hydrophilic of modification membrane was poor effect and the flux was low,but the compaction property of modification membrane was well.Thus,when the suitable proportion of two monomers was 40%～60%,the modified PVDF UF membrane had excellent properties and the flux and the retention rate reached 80mL/cm2·h and 80%,respectively.