Study On The Reinforced PVDF Hollow Fiber By Tubal Nonwovens

High strength composite PVDF hollow fiber membrane were prepared, using tubal nonwovens as reinforced layer which was prepared by PET fiber tube, diameter was 2.4mm。After coated by the PVDF membrane, composite membrane diameter was less than 2.6mm. The technological process and key equipments for the industrial purpose were also designed.This reinforced membrane possess high strength and pure water flux (PWF), tensile or rupture strength were up to 25MPa, burst pressure were 0.5MPa, and the highest PWF were 4200L/ m~2·h·atm ,which were much higher than that of the common ones.The effects of different factors on PWF, membrane construction, porosity, mean pore size, tensile or rupture strength and burst pressure were studied, containing concentration of PVDF, PVP and LiCl in coating solution, concentration of ethanol in bath-fed liquid and PET fiber mass. The SEM photographs showed that the tubular nonwovens of PET fiber were combined with the coating layer compactly. The coating layer was very thin and compact which looked like the skin layer in common PVDF hollow fiber membranes. With the increase of PVDF concentration in coating solution, PWF, porosity and mean pore size decreased, while burst pressure and tensile or rupture strength increased. Following with the rise of concentration of PVP in coating solution, PWF, porosity, mean pore size increased, however, burst pressure and tensile or rupture strength declined. PWF, membrane mean pore size, porosity, increased with enhance of the ethanol concentration bath-fed liquid, while the burst pressure and tensile or rupture strength decreased. The optimum time of thermal treatment on the tubular nonwovens, was available when the tube was baked. With the increase of PET fiber mass, burst pressure and tensile or rupture strength went up, but PWF, porosity and mean pore size decreased unconspicuously. Totally, the PET tube and PVDF layer both affected the composite membrane strength, while PWF, porosity and mean pore size were influenced by polymer solution.In this paper, tubal nonwoven was used as supporter, which was innovative comparing with the conventional method using non-woven fabrics as supporting. The contour machining device for the tubal nonwovens and the whole industry technology process to product the high strength PVDF hollow fiber were designed novelly.