Research Of Hydrophilic Modification Of PVDF Membranes

Polyvinylidene fluoride(PVDF) is a kind of white crystalline powdered polymer, with the prominent characteristics as high mechanical strength, good radiation resistance, good chemical stability, acid and alkali resistant erosion under the condition normal temperature. But in the actual application process due to the hydrophobic and oleophobic strong performance of C-F bond, the PVDF membrane is extremely easy dproduced the low efficiency problem adsorption separation in handing all kinds of wasteliquid. So it is very important for the hydrophilic modification on polyvinylidene fluoride membrane.The main contents of this paper is a kind of hydrophilic block copolymer was synthesised and using physical blending method on the hydrophilic modification of PVDF membrane in order to make preparation of the hydrophilic of PVDF membrane. First, we use the precipitation polymerization method to use F-113 as the solvent, using benzoyl peroxide(BPO) as initiator, with perfluoro iodine butane(TI-4) for iodine transfer agent, in a high-pressure reaction kettle for producing large molecular iodine transfer agent C4F9-PVDF-I.Then use the method of solution polymerization homemade C4F9-PVDF-I as large molecular iodine transfer agent, with N, N- two methyl formamide(DMF) as solvent with benzoyl peroxide,(BPO) as initiator was prepared with block copolymer PVDF-b-PtBA. Then the FT-IR spectroscopy and 1H NMR spectroscopy were used to characterize the structures of block copolymer PVDF-b-PtBA, and studied the self-assembly behavior of block copolymer, by scanning electron microscopy(SEM) observation of self-assembly morphology balling phenomenon.The synthetic block copolymer PVDF-b-PtBA, PVDF commercial product, polyethylene glycol(PEG-400) with DMF as solvent were used with configuration from the casting solution of different blending proportion. The use of membrane casting solution was prepared by phase inversion membrane of vinylidene fluoride hydrophilic. The hydrophilic test was performed using contact angle measurements on hydrophilic preparation of PVDF membrane, the contact angle was decreased from 94.7° to 58.5°; using the TGA method of heat stability test of PVDF membrane hydrophilicity. The thermal decomposition temperature of the hydrophilic PVDF film had a greater increase to 260℃. The mechanical strength of hydrophilic PVDF membrane reached 19MPa; SEM test results show that the uneven holes on the surface of H Hydrophilic modification of PVDF membranes.The experimental results show that iodine transfer agent C4F9-PVDF-I was synthesized successfully, and diblock copolymer PVDF-b-PtBA was synthesized by using the iodine transfer agent C4F9-PVDF-I, then the hydrophilic modification of PVDF membrane was prepared by using the block copolymer PVDF-b-PtBA. The hydrophilic modification of PVDF membrane showed that it showed good hydrophilic performance.