Surface modification method for polyvinylidene fluoride (PVDF) film or polyvinyl chloride (PVC) film

Abstract

The invention discloses a surface modification method for a polyvinylidene fluoride (PVDF) film or a polyvinyl chloride (PVC) film. The method is characterized by comprising the following steps of: (1) performing vacuum low temperature plasma treatment on the PVDF film or the PVC film at the power of 5 to 100W and the reaction vacuum degree of 2 to 100Pa for 1 to 20 minutes; and (2) mixing a solution which is formed by mixing methanol and deionized water and serves as a solvent, cuprous chloride or cuprous bromide serving as a catalyst, 2,2'-bipyridyl or a derivative thereof serving as a ligand, and sulphobetaine methyl methacrylate or allyl polyethylene glycol serving as a grafting monomer, controlling reaction temperature to 20-100 DEG C, and performing atom transfer radical polymerization (ATRP) reaction for 1 to 24 hours to obtain a product, wherein the molar ratio of the catalyst to the ligand is 1:(0.5-4), and the molar ratio of the film to the monomer is (100-0.1):1. The methodhas the advantages that: the hydrophilicity and anti-pollution capacity of the film can be improved, environment friendliness is achieved, and operation steps are simple.

Description

technical field [0001] The invention relates to a method for modifying the surface of a film, in particular to a method for modifying the surface of a polyvinylidene fluoride film or a polyvinyl chloride film. Background technique [0002] Polyvinylidene fluoride membrane (PVDF) and polyvinyl chloride membrane (PVC), as high-performance polymer membrane materials, are widely used in water treatment, protein separation, food processing and other related fields, but due to their strong hydrophobic effect , is susceptible to membrane fouling, so how to improve its hydrophilicity and increase its anti-fouling ability is the focus of current research. At present, the research on hydrophilic modification is mainly divided into two aspects: membrane surface modification and membrane material modification. The former is aimed at the modification of the finished membrane, while the latter is to modify the material first, and then use the phase transfer method to prepare a membrane w...

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Problems solved by technology

[0004] The existing Chinese journal Chemical Journal of Higher Schools (published February 2010, Volume 31, Issue 2, pp. 402-405) is published in the research on ATRP synthesis of graft copolymer PVDF-g-PNIPAAm and its separation membrane. Cuprous chloride (CuC1) / tris(N,N-dimethylaminoethyl)amine (Me 6 TREN) is a catalytic coordination system, using nitrogen nitrogen dimethylformamide (DMF) as a solvent, and directly grafting temperature-sensitive materials on commercial polyvinylidene fluoride (PVDF) powder by atom transfer radical polymerization (ATRP) N-isopropylacrylamide (NIPAAm), infrared spectroscopy (FTIR) and nuclear magnetic resonance (H NMR) analysis showed that PNIPAAm was successfully grafted onto PVDF, but the grafting rate was only about 4%, which made the membrane hydrophilic. Performance and anti-pollution properties cannot be greatly improved

[0005] At present, due to the good stability of PVDF membrane and PVC membrane, each with strong binding energy C-F bond and C-Cl bond, it is difficult for them to initiate ATRP reaction, so it is necessary to graft on the surface of the membrane first. The group containing halogen bromine or Cl, and then use this grafted group as the initiator to initiate the ATRP reaction, so the experiment is more complicated and the operation is cumbersome; at the same time, because it often needs to use strong acid, strong base and strong oxidant during the experiment Substances such as de-F or de-Cl are likely to cause harm to experimenters and cause environmental pollution

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