Preparation And Properties Of Network-enhanced UHMWPE/PVDF Binary Blend Microporous Membranes

Although the poly(vinglidene fluoride)membrane was used widely in membrane field.due to its chemical,thermal and mechanical properties.PVDF microporous membrane pore size to adjusted is difficult and mechanical properties is poor.In order to obtain high-performance PVDF micropore membrane in the process of preparating membrane,we commonly use physical blending,chemical grafting and surface modification method to improve membrane properties.Polymer and polymer blending,polymer and inorganic ions blending methods has been widely study.Although many properties of blending membrane were improved,mechanical properties became worse.In order to improving the comprehensive performance of membrane and obtain high-intensity PVDF membrane,ultrahigh-molecular-weight polyethylene(UHMWPE)/PVDF binary blend micropore membrane was preparated in this research by thermally induced phase separation(TIPS)using diluent mixture dibutyl phthalate(DBP)and Liquid paraffin(LP).This method is simple process can better improve membrane pore size,porosity,penetration and hydrophobic perproty and obtain high-intensity micropore membrane.The parper investigated effect of PVDF conten in polymer on blend membrane property using diluent LP by means of field emission scanning electron microscopy(FESEM),differential scanning calorimeter(DSC),contact angle,pore size and tensile strength test.In addition to,we also investigated effect of diluent proportion and polymer content on membrane property using diluent mixture.Important research contents and results as follows:Effect of PVDF content in polymer on membrane structure and property by TIPS and melt blend method preparaed using single diluent.Research result shows,with the increase of PVDF content in polymer,the roughness of the membrane surface is increased and the hydrophobicity is enhanced.The connectivity of inner pore increase when PVDF content increase in membrane.The membrane has the highest porosity and the best flux when the content of PVDF is 2wt%.The blend membrane has the highest intensity and the highest crystallinity of UHMWPE in membrane when the content of PVDF is 4wt%.The type and quantity of membrane pore increased by melt-blend method.We can charge micropore size by changing polymer content in process of perparated blend membrane.Effect of diluent proportion on casting solution performance and the morphological,structure,performance of the blend membrane using diluent mixture DBP and LP.Research result shows,with the increase of DBP proportion in diluent,the viscosity of casting solution decreased and the fluidity of casting solution increase.Besides,phase separation time increase in the process of temperature decrease.The above factors are conducive to the growth of droplets,so that the preparated membrane pore size increases and connectivity become better.On the other hand,with the increase of DBP proportion in diluent,membrane surface contact angle decrease and intensity decline,but the increase obviously of porosity,the gas flux and the water flux.Effect of PVDF content in polymer on the morphological,structure,performance of blend membrane using diluent mixture DBP and LP.Research result shows,PVDF distributed mainly in the membrane surface,UHMWPE network enhance structure distributed mainly inside the membrane.With the increase of PVDF content in polymer,the increase of the PVDF microspheres stacking thickness,The density between microspheres decreases,the membrane porosity,the gas flux and the water flux decrease.On the other hand,with the increase of PVDF content in polymer,the membrane contact angle,hydrophobicity and intensity increase.