Nonwoven Reinforced Polyvinyl Chloride Porous Membrane Research

As a polymer membrane material,PVC has great application value due to its flame retardant,acid and alkali resistance,good mechanical properties and low cost.In this study,the PVC porous membranes were fabricated by solution phase transformation method.The PVC as the membrane-forming polymer,GBL as solvent,and nonwoven fabric as reinforcement were used in this study.The effects of membrane formation conditions on membrane structure and properties were analyzed and discussed.The casting solution was prepared at 110? using PVC as the membrane-forming polymer and GBL as solvent,the PVC porous membranes were fabricated by solution phase transformation method with nonwoven fabric as reinforcement.The effects of PVC content and coagulation bath temperature on the porous membrane structure and properties were investigated.The results showed that the cross section of the prepared PVC porous membranes was homogeneous sponge pore structure without dense top surface.With the increase of PVC content,the viscosity of casting solutions was increased,which reduced the pore size of the membrane top surface and cross section and membrane porosity,increased the water contact angle.While the average pore diameter was decreased from 1.06?m to 0.25?m,and the pure water flux was decreased from 1050.40L/(m2·h)to 158.46 L/(m2·h).All of the prepared membranes'tensile strengthwas greater than 20MPa.The promotion of coagulation bath temperature would bring about the enhancement of micropores on the membrane surface and membrane porosity.The average pore size increased from 0.187?m to 0.48r?m,while the water contact angle,hydrophilicity and the pure water flux were increased obviously.This indicated that the increase of coagulation bath temperature was beneficial to improve the membrane permeability.The PVC porous membranes were fabricated by solution phase transformation method using PVC as membrane-forming polymer and GBL as solvent,polyethylene glycol(PEG)and amphiphilic polymer Pluronic-F127 as additives.The effects of the content and composition of PEG and Pluronic-F127 on the membranes structure and properties were investigated.The results showed that the using of hydrophilic additives was crucial to the formation of membrane surface pore structure.With the addition of hydrophilic additives,the membrane surface changed from dense and nonporous structure to loose porous structure,while thepore size of cross-section sponge structure,the membrane hydrophilicity,porosity and pure water flux were increased.At the same time,the tensile strength and elongation at break of prepared PVCmembranes were increased significantly.Compared with PEG,the amphiphilic polymer Pluronic-F127 could improve the membrane performance more effectively.With the increase of Pluronic-F127 content,the pores number of membrane surface and cross-section were increased,and the surface hydrophilicity,membrane porosity,average pore size,pure water flux and the tensile strengthwere increased.When Pluronic-F127 content reached to 10wt.%,the water contact angle dropped to 54.70°.the pure water flux and the tensile strength could reach to 901.45L/(m2·h)and 36.30MPa,respectively.Based on the principle of organic/inorganic phase interface theory,PVC/SiO2 hybrid porous membranes were fabricated by solution phase transformation method using hydrophilic.nano-SiO2 inorganic particles as additive.The influence of nano-SiO2 content on membrane structure and properties was investigated.The results showed that the obtained PVC/SiO2 hybrid porous had uniform sponge-like pore structure without obvious dense upper surface.With the increase of nano-SiO2 content,the average pore size of hybrid porous membrane showed a decreasing.trend.However,all of the membrane porosity,pure water flux and tensile strength were first increased and then decreased,while the elongation at break was decreased.When the nano-SiO2 content was 1wt.%,the obtained PVC/SiO2 hybrid porous membrane had better performance.