聚甲基丙烯酸甲酯/聚乙二醇单甲醚接枝共聚物的制备及对聚偏氟乙烯微孔膜的亲水改性

Preparation of Methyl Methacrylate/Polyethylene Glycol Monomethyl Ether Copolymer and Effect on Hydrophilic Modification of Polyvinylidene Fluoride Microporous Membrane

采用自由基聚合的方法制备了聚甲基丙烯酸甲酯/聚乙二醇单甲醚两亲性接枝共聚物(C-MMA/MA-MPEG),并用两亲性共聚物C-MMA/MA-MPEG对聚偏氟乙烯(PVDF)进行亲水性改性制备微孔膜。使用傅里叶变换红外光谱、核磁共振碳谱和凝胶渗透色谱对接枝共聚物结构和相对分子质量进行表征与分析,当MA-MPEG的摩尔含量为10%时,接枝聚合物的接枝率提高到8.9%,相对分子质量分布基本相同,稳定在2.0左右;用差示扫描量热仪对PVDF膜的热性能进行测试,PVDF微孔膜的熔融温度变化不明显,当C-MMA/MA-MPEG-4的添加量为20%时,结晶温度下降了8℃;用扫描电镜以及接触角测量仪对PP膜表面形貌结构与亲水性能进行测试,结果表明,其随改性剂用量的增多,亲水性得到提高,微孔膜的孔隙率也得到增大,当改性剂添加量为20%时,接触角降低到59.5°。

Amphiphilic graft copolymers C-MMA/MA-MPEG were prepared by free radical polymerization.Then the amphiphilic copolymers were used to modify the PVDF membranes.Fourier transform infrared spectroscopy(FT-IR),nuclear magnetic resonance(13C-NMR)and gel permeation chromatography(GPC)were used to analyze and characterize the structure and relative molecular weight of the graft copolymers.The results show that with the molar fraction of MA-MPEG increases to 10%,the grafting degree of C-MMA/MA-MPEG increases to 8.9%,and the molecular weight distribution remains around 2.0.The DSC results show that the melting temperature change of the PVDF microporous membranes is not obvious,when the C-MMA/MA-MPEG-4 content is about 20%,the crystallization temperature decreases by 8℃.he scanning electron microscope(SEM)and contact angle measuring instrument were used to test the surface morphology and hydrophilicity of PVDF membranes.With the increase of the modifier content,the hydrophilicity and the porosity of membranes are both improved.When the modifier content is 20%,the contact angle drops to 59.5°.