Study On The Regulation And Mechanism Of Pore Structure On The Surface Of PVC Membrane

Uniform pore structure membrane is a new type of separation membrane.The membrane with uniform pore structure has three advantages: high selectivity,high permeability,strong anti pollution and stability.Therefore,the uniform pore structure significantly improves three important parameters of membrane separation process.At present,the preparation methods of mesoporous structure show the possibility of constructing mesoporous structure in principle.However,from the perspective of membrane materials and separation applications,there are still obvious deficiencies in scale preparation,cost and pore regularity.Based on the low cost of PVC film preparation,this paper designs a synchronous self-assembly control method of PVC solution modification phase separation based on the low cost of PVC membrane preparation,and draws lessons from the amination modification of PVC materials and the self-assembly principle of polymer molecular chain in phase separation.The purpose of this paper is to adjust the double bond formation and self-assembly pore behavior of PVC chain "elimination reaction",so as to achieve the goal of forming uniform pore on the surface of PVC membrane and realizing the realization of the opposite The regulation of pore structure on PVC membrane surface.The modified PVC by adding EDA solution to the PVC casting solution was carried out.The microfiltration membrane with uniform pore size structure was prepared by the traditional nips method.Then,the mechanism of the formation of the uniform pore structure is analyzed and inferred by the comparison experiment.The mechanism of the self-assembly of the noncovalent bond is proposed.That is,the formation of the uniform pore structure is closely related to the existence of carbon carbon double bond and amine molecule.The relationship between the surface morphology and chemical bond composition of PVC film is characterized by atomic force infrared spectrometer and scanning electron microscope,and the mechanism is preliminarily verified.The effects of the amount of ethylenediamine,pre evaporation time,reaction temperature and reaction time on the pore structure of the membrane were further investigated.The results showed that the uniformity of pore size on the membrane surface was better when the amount of ethylenediamine was 4wt%,the reaction time was 6h and the reaction temperature was 70 ?.The results show that the pure water flux of the membrane is significantly improved compared with the original membrane,and the effect of the membrane is better for the sodium alginate.