Preparation And Characterization Of PP Microporous Membranes Via Thermally Induced Phase Separation

In this paper, polypropylene flat membrane was prepared via thermally induced phase separation (TIPS) method, the effect of influence factors on the performance of PP microporous membranes were investigated.Firstly,the screening of diluents to prepare PP membrane was proposed via combining solubility parameters,the transmittance curve and testing the mechanical strength of the samples.According to the fact,the optimum diluent to prepare PP membrane is DBP-TA mixed cosolvent.Secondly, the effect of tallow amine concentration on the morphologies and properties of PP-DBP-TA microporous membranes was investigated through the methods of SEM, porosity, water flux and so on. The result indicate that with the increasing of TA content in the casting solution, mean pore radius, porosity and flux increase, while the mechanical property of the membrane decrease.Thirdly, the effect of polypropylene concentration on the morphologies and properties of PP-DBP-TA microporous membranes was investigated.The flux, porosity and mean pore radius all decrease with the increasing of PP concentration.When PP concentration is 20wt%,flux is 120 L·m-2·h-1·bar-1, mean pore radius is about 3.2μm,and porosity is 61%.Using TH3988 and NA-40 as nucleating agent, the effect of nucleating agent concentration on the morphologies and properties of microporous membranes was investigated. Compare TH3988 with NA-40,the structure of polypropylene membrane added TH3988 is more compact. With the increasing of temperature of coagulating bath, mean pore radius,porosity and flux increase,while the mechanical property of the membrane decrease.DOP coagulating bath is better than soybean oil coagulating bath in improvement of water flux.