PVDF及其共聚物膜的耐碱性能研究  

Research on alkali resistance of PVDF and its copolymer membranes

作　　者：叶灿 周玥 刘飞 汪效祖 汪朝晖 崔朝亮 YE Can;ZHOU Yue;LIU Fei;WANG Xiaozu;WANG Zhaohui;CUI Zhaoliang(State Key Laboratory of Materials-Oriented Chemical Engineering,College of Chemical Engineering,Nanjing Tech University,Nanjing 211816,China)

机构地区：[1]南京工业大学化工学院材料化学工程国家重点实验室,南京211816

出　　处：《膜科学与技术》2022年第1期72-79,共8页Membrane Science and Technology

基　　金：国家重点研发计划(2017YFC0403702);国家自然科学基金(22078146);江苏省人力资源和社会保障厅六大人才高峰(JNHB-036)。

摘　　要：本文以聚偏氟乙烯(PVDF)、聚偏氟乙烯-六氟丙烯(PVDF-HFP)和聚偏氟乙烯-三氟氯乙烯(PVDF-CTFE)为膜材料,采用非溶剂诱导相分离法(NIPS)制备超滤、微滤膜.聚合物含量为20%(质量分数,下同),添加剂含量为6%,溶剂DMAc含量为74%.使用场发射扫描电子显微镜(FESEM)、傅里叶红外光谱仪(FTIR)等仪器对制备的3种膜进行表征.碱性环境采用浓度为0.01、0.1、1、3和5 mol/L的氢氧化钠溶液构建,考察3种聚合物膜分别浸泡50 h后的耐碱性能.5 mol/L NaOH溶液浸泡50 h后,PVDF膜、PVDF-HFP膜以及PVDF-CTFE膜的断裂伸长率分别下降了95.3%、30.7%和22.6%;PVDF膜和PVDF-HFP膜的强度分别下降了34.5%和11.5%,PVDF-CTFE膜的强度没有明显降低.结果表明,同等级碱性环境中,两种共聚物膜的力学性能均优于PVDF膜,可塑性更好.拉曼光谱测试结果表明,聚合物脱氟化氢形成碳碳双键,且脱氟化氢导致膜颜色变深,膜在碱液中发生降解,但两种共聚物膜的降解程度远低于均聚物膜.In this paper,polyvinylidene fluoride(PVDF),polyvinylidene fluoride-hexafluoropropene(PVDF-HFP)and polyvinylidene fluoride-trifluoroethylene chloride(PVDF-CTFE)were used as membrane materials to prepare ultrafiltration and microfiltration membranes by Non-solvent induced phase separation(NIPS)method.The formula contains 20%polymer,6%additive and 74%solvent DMAc.Field emission scanning electron microscopy(FESEM),Fourier infrared spectroscopy(FTIR)and whiteness meter were used to characterize the three kinds of membranes prepared.Concentrations of 0.01,0.1,1,3 and 5 mol/L sodium hydroxide solution was used to construct the alkaline environment.The alkali resistance of the three polymer membranes was investigated after immersion for 50 h.After soaking in 5 mol/L NaOH solution for 50 h,the elongation at break of PVDF,PVDF-HFP and PVDF-CTFE membranes respectively decreased by 95.3%,30.7%and 22.6%.The strength of PVDF membrane and PVDF-HFP membrane respectively decreased by 34.5%and 11.5%,while PVDF-CTFE membrane did not decrease significantly.The results show that the mechanical properties and plasticity of the two copolymer membranes were better than that of PVDF membranes in the same alkaline environment.The results of Raman test show that the polymer defluorinated hydrogen formed carbon-carbon double bond,the defluorinated hydrogen resulted in the darkening of the membrane color and the degradation of the membrane in alkali solution,but the degradation degree of the two copolymer membranes was much lower than homopolymer membranes.

关 键 词：PVDF PVDF-HFP PVDF-CTFE 耐碱性 

分 类 号：TQ031.4[化学工程]