Tianjin Polytechnic University

Tianjin Motimo Membrane Technology Co., Ltd.

Changfa Xiao

Shulin An

Qinglin Huang

Jian Zhao

Chun Wang

Mingxing Chen

Hailiang Liu

Xiaoyu Hu

Junqiang Hao

Jingjing Yan

Xiaodong Zhang

Zhongqing Miao

Xiao Hu

Haixian Liang

Jianli Liu

Dan Guo

Wujiang Zhang

Ruobing Hou

Naiku Xu

Tai Zhang

Yan Feng

Guangxia Jia

Nana Li

Weiwei Yin

Zitao Wang

Disclosed is a polyvinylidene fluoride/ultra-high molecular weight polyethylene blend microporous membrane and preparation method thereof, which belongs to the field of microporous membrane. The blend microporous membrane has good hydrophobicity, mechanical properties and permeability. The preparation method includes: preparing a suspension by polyvinylidene fluoride, ultra-high molecular weight polyethylene, antioxidant and diluent; then feeding the obtained suspension into a twin-screw extruder, and the cast membrane gel extruded from the outlet is directly injected into a metal mold for injection molding; the mold temperature and the outlet temperature of the extruder are the same, and the cavity surface of the mold has micro-prism array structure; then cooling the mold in aqueous medium to obtain a nascent gel membrane; drying the obtained nascent gel membrane in a freeze dryer after removal of the diluents by extraction. The prepared membrane can be used in the membrane separation technology such as membrane distillation.

Polyvinylidene fluoride/ultra-high molecular weight polyethylene blend microporous membrane and preparation method thereof

A homogeneous fiber reinforced PVDF hollow fiber membrane and a preparation method thereof are provided. The membrane includes a hollow tubular reinforcement made of PVDF fibers and a polymer separation layer made of PVDF casting solution; wherein the polymer separation layer casting solution comprises 4-25% PVDF resin, 5-20% pore-forming agent, 0-3% inorganic particles and 52-91% solvent according to mass fraction. The preparation method includes steps of: (1) preparing a hollow tubular reinforcement made of PVDF fibers; (2) preparing a PVDF polymer separation layer casting solution; and (3) obtaining the homogeneous fiber reinforced PVDF hollow fiber membrane.

Homogeneous fiber reinforced PVDF hollow fiber membrane and preparation method thereof

A reinforced oil-absorptive membrane material, includes: a tubular support () and an oil absorbing layer () provided on a surface of the tubular support (), wherein a plurality of holes are provided on the tubular support (); and the oil absorbing layer () is a piece of nonwoven fabric with a polymer layer provided thereon. The reinforced oil-absorptive membrane material has an excellent oil-absorbing and supportive performance, and is capable of being utilized continuously in a negative pressure suction manner and thus shows high oil absorption efficiency. A method for manufacturing the reinforced oil-absorptive membrane material including pre-treating the nonwoven fabrics by aqueous alkali, covering a membrane casting solution including a solvent, a graphene, polyvinylidene fluoride, pore-forming agent and inorganic particle, and then solidifying and extracting to obtain the oil-absorbing layer.

Reinforced oil-absorptive membrane material, unit and preparation method thereof

The present invention discloses a hydrophobic-oleophilic and hollow fiber composite membrane and preparing method thereof. A preparing method includes preparing hollow tubular braids by two-dimensional braided technique using polyester filaments, wherein the hollow tubular braids are used as the reinforcements. The method further includes mixing polyvinylidene fluoride, hydrophobic pore-forming agent, and the rest of solvent to prepare a casting solution of surface separation layer. The method further includes pre-treatment processing of the reinforcements; and coating the casting solution of surface separation layer on the outer surface of the processed reinforcements through a spinning spinneret to form a primary membrane. The reinforcements are replaced by the primary after post-processing, and repeating the coating process.

Hydrophobic-oleophilic hollow fiber composite membrane and preparing method thereof

A hollow tubular oil absorbing material includes: a core formed by a spring, and an outer shell formed by a flat sponge wrapped at the spring; wherein the flat sponge is fixed at both ends of the spring; the flat sponge fully covers all the spring or is sealed at a first end; a connecting tube is connected at a second end of the spring for communicating with a vacuum pump; a graphene oxide layer is coated at the outer sponge. The graphene oxide layer on the flat sponge of hollow tubular oil absorbing material is formed by immersion and coating under negative pressure. Further the reduction of graphene oxide is performed with hydrazine hydrate steam and followed by washing and drying. Finally, a hollow tubular oil absorbing material with a spring core and an outer grapheme-coated sponge structure is obtained, which can be applied to continuous oil-water separation.

Hollow tubular oil absorbing material and preparing method thereof

A method for preparing a homogeneous braid-reinforced (HMR) PPTA hollow fiber membrane combines PPTA hollow tubular braids with PPTA surface separation layer. The method includes following steps of: (1) preparing the PPTA hollow tubular braids, wherein the PPTA hollow tubular braids which are made from PPTA filament yarns are woven by a two-dimensional braided method, the outer diameter of the PPTA tubular braids is 1-2 mm; (2) preparing the PPTA casting solution as the surface separation layer, wherein the 1-3 wt % PPTA resin, 0-2 wt % inorganic particles and 10-20 wt % pore-forming agents are mixed into 75-89% inorganic acid solvent, stirred for 1-3 hours at 70&#xb0; C.-90&#xb0; C. to form homogeneous and transparent casting solution; and (3) preparing reinforced PPTA hollow fiber membrane, wherein the casting solution as the surface separation layer is evenly coated on the surfaces of the PPTA hollow tubular braids through spinneret, and they are immersed in a coagulation bath for solidified formation.

Method for preparing homogeneous braid-reinforced PPTA hollow fiber membrane

A method for preparing an aromatic polyamide porous hollow fiber membrane firstly premixes PPTA resin, solvent, composite pore-forming agents and inorganic particles in a stirring vessel to form casting solution, secondly injects the casting solution into a double-screw extruder to be fully dissolved under the effect of shear force and enters a spinneret via a metering pump. The PPTA hollow fiber membranes are prepared by the dry-wet spinning method, which solves the problems that hard pore-forming and low porosity in the preparation process of PPTA porous membrane. Utilization of the double-screw extruder is capable of greatly shortening the dissolved time and the deaeration time. Meanwhile the increase of PPTA in casting solution also improves mechanical properties of the PPTA membrane. The addition of the inorganic particles improves mechanical toughness and enhance pure water flux, hydrophilia and rejection rate.

Method for preparing aromatic polyamide porous hollow fiber membrane

A preparation method of a perfluorinated polymer hollow fiber membrane comprises: evenly mixing a first mixture that is mixed by a perfluorinated polymer, PS, a polymer additive, and a composite pore-forming agent; evenly mixing a second mixture that is mixed by the first mixture and an organic liquid; under 300&#xb0; C.-350&#xb0; C., processing the second mixture with a melt to spin by a twin-screw extruder; extruding a hollow fiber by a hollow fiber spinneret; dipping the hollow fiber membrane into deionized water for 48 hours; putting the hollow fiber membrane aired into a concentrated sulfuric acid to process with a sulfonation; washing the hollow fiber membrane by deionized water; and drying the hollow fiber membrane; in such a manner that the hydrophilic perfluorinated polymer hollow fiber membrane is obtained.

Preparation method of perfluorinated polymer hollow fiber membrane

A composition for preparation of a hollow fiber porous membrane including 40-60 wt. % a polymer matrix, 20-30 wt. % an organic mixed solution, and 20-40 wt. % a water-soluble substance. The polymer matrix is a polymer capable of dissolving in an organic solvent and melt processing. The organic mixed solution is a mixture comprising 60-90 wt. % a first liquid soluble to the polymer matrix and 10-40 wt. % a second liquid insoluble to the polymer matrix. The water-soluble substance is a water-soluble polymer, a low molecular weight water-soluble particle, or a mixture thereof. A method for producing the hollow fiber porous membrane using the composition including a) preparing the organic mixed solution, b) mixing the components of the composition, c) applying melt spinning, d) drawing, and e) washing. The hollow fiber membrane has high strength, large flux, and low cost.

Composition for preparation of hollow fiber porous membrane and preparation method using the same

A method for making a liquid separation membrane, including: (1) providing a polyvinylidene fluoride liquid separation membrane or polypropylene liquid separation membrane prepared by a thermally induced phase separation method as a substrate membrane, soaking the substrate membrane with water or a weak polar organic liquid to make membrane pores of the substrate membrane filled with the liquid, the soaking time being between 0.5 s and 1 min, and the weak polar organic liquid being indissolvable and compatible with the polyvinylidene fluoride liquid separation membrane or polypropylene liquid separation membrane; (2) coating a casting solution of polyvinylidene fluoride on the surface of the soaked substrate membrane obtained in step (1), and quickly soaking the substrate membrane in a coagulating bath heated to a temperature of 60-100&#xb0; C. for curing to yield the liquid separation membrane.

Method for making liquid separation membrane

A method of preparing oil-absorbing fibers by: a) fully dissolving a dispersant and a deionized water in a reaction vessel, adding a methacrylate monomer and an initiator to a reactor and stirring to form a homogenous solution, transferring the homogenous solution into the reaction vessel, charging nitrogen gas, stirring, raising temperature to 70-80&#xb0; C., allowing to react for 2-6 hours, raising temperature to 90-100&#xb0; C., allowing to react for 2-4 hours, collecting a resultant product, washing, drying, and obtaining a white resin; b) drying the white resin, mixing with a swelling agent, and sealing the mixture at room temperature for 48-96 hours to yield a homogenous gel; c) grinding the gel completely, spinning by a plunger spinner, and coagulating with a coagulation bath to yield an as-spun oil-absorbing fiber; and d) drawing the as-spun oil-absorbing fiber with a draw ratio of 2-6 to yield oil-absorbing fibers.

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Tianjin, China

Changfa Xiao