Research On The Structure Regulation And Performance Of Homogeneous Reinforced Polyvinyl Chloride Hollow Fiber Membrane

In this paper,the high-strength and high-flux polyvinyl chloride(PVC)hollow fiber porous membrane prepared via melt-spinning and on-line stretching technology was used as the matrix membrane.The homogenous-reinforced PVC hollow fiber membrane with high-strength and high separation precision was fabricated by uniformly coating the polymer solution on the surface of the matrix membrane through dry-wet spinning technology.Then the structure of homogenous-reinforced PVC hollow fiber membrane was adjusted to optimize its comprehensive performance.The PVC as the polymeric material,Gamma-butyrolactone(GBL)as the solvent,epoxidized soybean oil(ESO)as the thermal stabilizer,polyethylene glycol(PEG)20000 and composite powder as the pore-creating agent were used to prepare the PVC hollow fiber porous membrane by melt-spinning and on-line stretching technology.The effects of different on-line stretching ratios on the structure and performance of obtained PVC hollow fiber porous membrane were researched.The results showed that the PVC hollow fiber porous membrane was a kind of homogenous sponge-like pore structure.The membrane surface became smooth,while the water contact angle,mean pore size,porosity and pure water flux were increased with the increase of the stretching ratio.The rejection of Direct Black 19 particles was higher than 90%.The prepared PVC hollow fiber membrane exhibited excellent mechanical properties.The tensile strength reached 23.89 MPa when the stretching ratio was 3.0.The PVC hollow fiber membrane porous membrane obtained by melt-spinning and on-line stretching technology was used as the matrix membrane.The homogenous-reinforced PVC hollow fiber membrane was fabricated by uniformly coating the polymer solution on the surface of the matrix membrane through dry-wet spinning technology.The influence of different contact time and the mixed solvent composition(N,N-dimethylacetamide(DMAc)/triethyl phosphate(TEP)/glycerol)on the structure and properties of homogenous-reinforced PVC hollow fiber membrane were investigated.The results showed that a dense interfacial layer was formed between the matrix membrane and the separation layer of the homogenous reinforced PVC hollow fiber membrane.The shorter the contact time between the casting solution and the matrix membrane was,the thinner interface layer was,which could improve the permeability of the obtained membrane.With the increase of the ratio of TEP/glycerol in the mixed solvent,the dense interfacial layer of the homogenous-reinforced PVC hollow fiber membrane became thinner,while the sponge-like sublayer became thicker and the surface pore size increased.When the DMAc/TEP/glycerol was 80/15/5,the interface became macroporous structure,while the finger-like pores of the separation layer disappeared completely and became sponge-like pore structure.The homogenous-reinforced PVC hollow fiber membranes obtained the largest mean pore size,porosity and pure water flux as DMAc/TEP/glycerol was 70/30/0.The breaking strength of homogenous-reinforced PVC hollow fiber membrane was more than 11 MPa and the elongation at break was more than 35%.