Method for modifying interpenetrating polymer network on surface of polyvinylidene fluoride porous membrane

A polyvinylidene fluoride and interpenetrating polymer technology, applied in the field of separation membrane technology and membrane materials, can solve the problems of separation index decline, large driving force, and restricted application

Active Publication Date: 2011-08-17
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, polyvinylidene fluoride is a kind of hydrophobic polymer, and its hydrophobicity will cause two problems: one is that the separation process requires a large driving force; The main separation index decreases and the service life of the membrane is shortened, which restricts its application in water phase systems such as biochemical pharmaceuticals, food and beverage, and water purification. Therefore, the hydrophilic modification of polyvinylidene fluoride has important practical significance
The advantage of surface grafting is that the hydrophilization effect is good and the hydrophilicity is long-lasting. The disadvantage is that the hydrophilization process is complicated.
[0004] Regarding the research on improving the solvent resistance of polyvinylidene fluoride porous membranes, there is no corresponding patent report in China at present.

Method used

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  • Method for modifying interpenetrating polymer network on surface of polyvinylidene fluoride porous membrane
  • Method for modifying interpenetrating polymer network on surface of polyvinylidene fluoride porous membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] The polyvinylidene fluoride / N,N-dimethylacetamide solution with a polymer weight percentage of 25% is cast on a glass plate, and water is used as a coagulant, and a polyvinylidene fluoride porous flat film is prepared by a dry-wet method. Pure water flux is 600~700L / m 2 · h · 0.1MPa.

[0053] Soak the polyvinylidene fluoride flat film in an aqueous solution containing 1% polyvinyl alcohol and 0.2% glutaraldehyde for 10 minutes; then the polyvinylidene fluoride adsorbed polyvinyl alcohol and glutaraldehyde The ethylene porous membrane is immersed in an aqueous solution containing amine compounds, wherein the aqueous solution containing amine compounds contains ethylenediamine with a mass concentration of 50% and phosphoric acid with a mass concentration of 1%. The water temperature is controlled at 40°C. After reacting for 10 hours, soak in deionized water at 30°C for 12 hours to obtain a polyvinylidene fluoride porous membrane modified by a surface interpenetrating pol...

Embodiment 2

[0056] In Example 1, the N,N-dimethylformamide solution of the used polyvinylidene fluoride was spun through an annular spinneret, and this was all using water as the core liquid and the coagulation liquid. A hollow fiber membrane with an outer diameter of 1.6mm and an inner diameter of 0.9mm was obtained, and the pure water flux of the hollow fiber membrane was 600-700L / m 2 · h · 0.1MPa.

[0057] Then, the hollow fiber membrane was cross-linked in the same manner as in Example 1, wherein the aqueous solution containing amine compounds contained 90% ethylenediamine and 2% phosphoric acid. The pure water flux of the cross-linked hollow fiber membrane is 650-750L / m 2 · h · 0.1MPa, after 120 hours of continuous operation, the measured flux remains at 650-750L / m 2 · h · 0.1MPa. The prepared membrane was dried in an oven at 50°C for 24 hours, and then rehydrated directly after taking it out. The measured pure water flux was 550-600L / m 2 · h · 0.1MPa.

[0058] The cross-linked ...

Embodiment 3

[0060] Put the polyvinylidene fluoride resin and benzophenone into a high-temperature stirring tank and heat up It becomes a polymer homogeneous solution at 200°C, and then it is spun through a ring-shaped spinneret. The core liquid is glycerol, and water is used as a coagulation bath. A hollow fiber membrane with an outer diameter of 1.6mm and an inner diameter of 0.9mm was obtained, and the pure water flux of the hollow fiber was 800-1000L / m 2 · h · 0.1MPa.

[0061] Then, the hollow fiber membrane is carried out cross-linking reaction in the same manner as in Example 1, wherein the aqueous solution containing the amine compound contains 50% hexamethylenediamine, 40% methylamine and 1.5% phosphoric acid . The pure water flux of the cross-linked hollow fiber membrane is 850-1100L / m 2 · h · 0.1MPa, after 120 hours of continuous operation, the measured flux remains at 850-1100L / m 2 · h · 0.1MPa. The prepared membrane was dried in an oven at 50°C for 24 hours, and then rehyd...

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Abstract

The invention provides a modifying method for interpenetrating polymer networks on the surface of a polyvinylidene fluoride porous membrane. The method is characterized by comprising the following steps: soaking the surface of the polyvinylidene fluoride porous membrane into an aqueous solution of vinyl alcohol polymer and aldehydes compound, and then into the aqueous solution containing amine compound which performs cross bonding with polyvinylidene fluoride on the surface of the polyvinylidene fluoride porous membrane; meanwhile, performing cross linking reaction with the aldehydes compoundon the surface of the polyvinylidene fluoride membrane by vinyl alcohol hydrophilic polymer, alternately performing two non-interfering cross linking reactions at the same time, realizing the entanglement between molecules on the surface of the polyvinylidene fluoride membrane, forming a hydrophilic structure with the interpenetrating polymer networks, and realizing the permanent hydrophilicity and solvent tolerance of the polyvinylidene fluoride porous membrane.

Description

technical field [0001] The invention belongs to the field of separation membrane technology and membrane materials, and in particular relates to a method for modifying an interpenetrating polymer network on the surface of a polyvinylidene fluoride porous membrane. Background technique [0002] Polyvinylidene fluoride has excellent thermal stability, corrosion resistance, non-flammability, anti-ultraviolet aging and other properties, and has high strength and wear resistance, so it has attracted extensive attention in the field of separation membranes in recent years. In terms of microfiltration and ultrafiltration, polyvinylidene fluoride has been used as a membrane with excellent performance. However, polyvinylidene fluoride is a kind of hydrophobic polymer, and its hydrophobicity will cause two problems: one is that the separation process requires a large driving force; The main separation index decreases and the service life of the membrane is shortened, which restricts ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/34B01D67/00
CPCB01D71/34B01D2323/30B01D67/0093
Inventor 王晓琳林亚凯田野杨健马文中马恒宇唐元晖
Owner TSINGHUA UNIV
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