以超临界二氧化碳为介质的碱预处理PVDF膜的疏水改性

Hydrophobic modification of alkali pretreatment PVDF membrane in supercritical carbon dioxide

用碱对PVDF膜进行预处理,以超临界二氧化碳(CO_(2))为介质,二甲基甲酰胺为引发剂,将含氟单体G60C接枝到PVDF膜上,改善膜的疏水性。分别探讨了超临界CO_(2)温度、压力对PVDF膜疏水改性的影响。结果表明:采用碱预处理对PVDF膜在超临界CO_(2)中的疏水改性是可行的;PVDF膜经过超临界CO_(2)疏水接枝改性后能够达到较好的疏水效果;在15.5 MPa、3 h、35℃条件下溶胀,27.5 MPa、125℃、6 h条件下接枝,PVDF膜疏水改性效果比较好。

The PVDF membrane was pretreated with alkali,and the fluorinated monomer G60C was grafted to the PVDF membrane with supercritical carbon dioxide(scCO_(2))as the medium and dimethylformamide as the initiator to im⁃prove the hydrophobicity of the membrane.The effect of different temperature and pressure of scCO_(2) on the hydrophobic modification of PVDF membrane was discussed.The results show that the alkali pretreatment is feasible to hydrophobic modification of PVDF membrane in scCO_(2).PVDF membrane can achieve better hydrophobic effect by graft modification in scCO_(2).The hydrophobic modification effect of PVDF membrane was relatively good when it swelled at 15.5 MPa,3 h,35℃and grafted at 27.5 MPa,125℃,6 h.