Preparation Of Copoly(phthalazinone Biphenyl Ether Sulfone) Blend Hollow Fiber Ultrafiltration Membranes

At present,ultrafiltration technology has been widely used in water treatment,food,chemicals,petroleum,environmental protection and other fields.The exploration and development of membrane materials are important,since it is the basis of the membrane separation technology.In current work,the novel copoly(phthalazinone biphenyl ether sulfone)(PPBES)material with excellent comprehensive properties was used as membrane materials.A series of PPBES hollow fiber substrates were prepared by changing the polymer dope formulation.Firstly,the results of cloud point titration suggested that the addition of polyvinylpyrrolidone(PVP)reduced the stability of the polymer solution and accelerated the rate of phase separation.It was found that the water flux reach up to 138 L/m~2h when the content is 2%.In addition,the water flux of hollow fiber membrane decreased with the increase of PPBES content,while the rejection rate of bovine serum albumin(BSA)increased.The effect of water on the structure and properties of hollow fiber membranes was studied.The result showed that when 0.2%water was added,the water flux was 135 L/m~2h and the rejection rate for BSA was 94%.Poly(ether sulfone)(PES)and PPBES were blended to increase the types of membrane materials,and the blends were used as membrane materials to prepare the hollow fiber blend membranes.The compatibility of the two polymers was firstly examined for determining the optimal ratio of PES to PPBES.It indicated that the compatibility was worse gradually with increase of PPBES content.A series of blend membranes were prepared by changing the ratio of PES and PPBES.The results showed that the pore diameter of the finger pores and the water flux both increased with the increase of PPBES content,and all of the rejection rates of BSA were maintained at 90%at least.In addition,the rotational viscosity of the casting solution and the thickness of the surface layer in the blend membrane both gradually increased with the increase of polymer concentration.So the water flux gradually decreased and the rejection rate of BSA gradually increased.The effects of different additives on the structure and properties of the blend membranes were also investigated.The results were as follows:the water flux decreased as the content of PVP increased from 0.5%to 2.0%;the water flux increased while the BSA retention rate decreased with the increase of glycol and butanone;when water was additive,the water flux decreased at first and then increased with the increase of water,and the rejection rate for BSA was maintained at high level.The effect of spinning conditions on the structure and properties of the blend membrane was investigated.The results showed that the outer diameter of the hollow fiber membrane decreased and the wall thickness became smaller with the increase of the winding speed.Besides,the water flux increased and the rejection rate of BSA decreased with increasing coagulation bath temperature.And the water flux increased at first and then decreased with the increasing air distance.