阅读说明：本技术 一种超疏水聚丙烯微孔膜及其制备方法 (Super-hydrophobic polypropylene microporous membrane and preparation method thereof ) 是由 关毅鹏 赵曼 田新霞 李晓明 车振宁 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种超疏水聚丙烯微孔膜,包括聚丙烯微孔基膜和构筑于其表面的超疏水层；所述超疏水层由疏水纳米粒子掺混聚合物制备而得；利用疏水纳米材料与高分子长链间交缠作用,在聚丙烯微孔膜表面构筑一层既均匀又稳固,既微观形貌粗糙,又表面能低的超疏水层,得到超疏水聚丙烯微孔膜。首先,将疏水纳米粒子与溶剂混合,在强烈搅拌和超声共同作用下,逐渐加入聚合物使之溶解,得到均相混合液；然后,将聚丙烯微孔基膜浸泡于上述混合液中反应,随后取出晾干、烘干后所得即为超疏水聚丙烯微孔膜。本发明所用原料来源广泛,价格低廉,制备过程简单可控,膜表面疏水性能大大提高,接触角甚至可达到160°以上,可满足多种疏水微孔膜的使用要求。(The invention discloses a super-hydrophobic polypropylene microporous membrane, which comprises a polypropylene microporous base membrane and a super-hydrophobic layer constructed on the surface of the polypropylene microporous base membrane; the super-hydrophobic layer is prepared by blending hydrophobic nano particles with a polymer; by utilizing the interlacing action between the hydrophobic nano material and the high polymer long chain, a super-hydrophobic layer which is uniform and stable, rough in microscopic appearance and low in surface energy is constructed on the surface of the polypropylene microporous membrane, so that the super-hydrophobic polypropylene microporous membrane is obtained. Firstly, mixing hydrophobic nano particles with a solvent, and gradually adding a polymer to dissolve the hydrophobic nano particles under the combined action of strong stirring and ultrasound to obtain a homogeneous mixed solution; and then, soaking the polypropylene microporous base membrane in the mixed solution for reaction, taking out, airing and drying to obtain the super-hydrophobic polypropylene microporous membrane. The raw materials used in the invention have wide sources, low price, simple and controllable preparation process, greatly improved hydrophobic property of the membrane surface, contact angle even reaching more than 160 degrees, and can meet the use requirements of various hydrophobic microporous membranes.)

1. A super-hydrophobic polypropylene microporous membrane is characterized in that: the super-hydrophobic polypropylene microporous membrane comprises a polypropylene microporous base membrane and a super-hydrophobic layer constructed on the surface of the polypropylene microporous base membrane; the super-hydrophobic layer is prepared by blending hydrophobic nano particles with a polymer; the hydrophobic nanoparticle blend polymer includes hydrophobic nanoparticles, a polymer, and a solvent.

2. The superhydrophobic polypropylene microporous membrane according to claim 1, wherein the hydrophobic nanoparticle blend polymer comprises the following components in percentage by mass: 0.2-5%/0.1-5%/90.0-99.7%, the sum of the mass percentages is 100%.

3. The superhydrophobic polypropylene microporous membrane of claim 1, wherein the hydrophobic nanoparticles are one or more of hydrophobic graphene, hydrophobic carbon nanotubes, hydrophobic metal organic frameworks, and hydrophobic silica; the particle size of the hydrophobic nano particles is 10 nm-300 nm.

4. The superhydrophobic polypropylene microporous membrane of claim 1, wherein the polymer is one or more of polypropylene, polyethylene, polyvinyl chloride, and polyvinylidene fluoride.

5. The superhydrophobic polypropylene microporous membrane according to claim 1, wherein the solvent is one or more of cyclohexanone, xylene, tetrahydrofuran, ethyl acetate and dichloroethane.

6. The superhydrophobic polypropylene microporous membrane of claim 1, wherein the polypropylene microporous base membrane is in the form of one of a hollow fiber membrane, a tubular membrane, and a flat sheet membrane.

7. The method for preparing the superhydrophobic polypropylene microporous membrane according to any one of claims 1 to 6, comprising the steps of:

mixing hydrophobic nano particles with a solvent, and gradually adding a polymer to dissolve the hydrophobic nano particles under the combined action of strong stirring and ultrasound to obtain a homogeneous mixed solution;

and step two, soaking the polypropylene microporous base membrane in the hydrophobic nano particle blended polymer mixed solution prepared in the step one for 60 s-12 h, taking out, airing, and drying at the drying temperature of 60-150 ℃ for 0.5-12 h to obtain the superhydrophobic polypropylene microporous membrane.

Technical Field

The invention relates to a preparation method of a super-hydrophobic polypropylene microporous membrane, which can be used in the fields of membrane absorption desulfurization, deamination, decarburization, degassing, membrane distillation, membrane crystallization and the like.

Background

Microporous polypropylene membranes have many advantages: high strength, high extensibility and high elasticity; a reticulated pore structure (high water permeability, high retention); good chemical resistance. Because the polypropylene microporous membrane takes polypropylene (PP) as a raw material, the polypropylene microporous membrane has the advantages of good impact property, large unit membrane area, high separation efficiency, high wear resistance and the like. Therefore, the method is widely applied to the related fields of membrane desulfurization, deamination, decarburization, degassing, membrane distillation, membrane crystallization and the like.

However, due to membrane infiltration, etc., polypropylene microporous membranes are prone to wet permeation during application, which results in reduced membrane effectiveness or even no membrane availability in desulfurization, deamination, decarburization, degassing, membrane distillation, and membrane crystallization related applications.

The superhydrophobic film has excellent anti-wetting properties due to its high surface roughness and low surface energy. At present, a method for constructing a rough surface or reducing surface energy is mainly adopted to prepare the super-hydrophobic film, the former is commonly used by a vapor deposition method or a surface etching method, wherein the vapor deposition method needs expensive equipment, the template method has low preparation efficiency, and the surface etching method has poor treatment effect stability; the latter is to modify low surface energy material on the surface, and the commonly used low surface energy material is fluorocarbon resin, fluorosilicone resin, organic silicon resin, etc. The existing low surface energy material can obtain a super-hydrophobic surface, but the super-hydrophobic surface loses super-hydrophobicity due to the influence of external environment such as high temperature, high humidity, certain mechanical friction and the like when in use.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a preparation method of a super-hydrophobic polypropylene microporous membrane. By utilizing the interlacing action between the hydrophobic nano material and the high polymer long chain, a super-hydrophobic layer which is uniform and stable, rough in microscopic appearance and low in surface energy is constructed on the surface of the polypropylene microporous membrane, so that the super-hydrophobic polypropylene microporous membrane is obtained. The invention has the advantages of wide source of raw materials, low price, simple and controllable preparation process, greatly improved hydrophobic property of the membrane surface and capability of meeting the use requirements of various hydrophobic microporous membranes.

In order to solve the technical problems, the invention provides a super-hydrophobic polypropylene microporous membrane, which comprises a polypropylene microporous base membrane and a super-hydrophobic layer constructed on the surface of the polypropylene microporous base membrane; the super-hydrophobic layer is prepared by blending hydrophobic nano particles with a polymer; the hydrophobic nanoparticle blend polymer includes hydrophobic nanoparticles, a polymer, and a solvent.

Further, the super-hydrophobic polypropylene microporous membrane of the invention comprises: in the hydrophobic nano particle blended polymer, the mass percentages of the hydrophobic nano particle, the polymer and the solvent are as follows: 0.2-5%/0.1-5%/90.0-99.7%, the sum of the mass percentages is 100%.

The hydrophobic nano-particles are one or more of hydrophobic graphene, hydrophobic carbon nano-tubes, hydrophobic metal organic frameworks and hydrophobic silicon dioxide; the particle size of the hydrophobic nano particles is 10 nm-300 nm.

The polymer is one or more of polypropylene, polyethylene, polyvinyl chloride and polyvinylidene fluoride.

The solvent is one or more of cyclohexanone, xylene, tetrahydrofuran, ethyl acetate and dichloroethane.

The polypropylene microporous base membrane is in the form of one of a hollow fiber membrane, a tubular membrane and a flat membrane.

The preparation method of the super-hydrophobic polypropylene microporous membrane comprises the following steps:

mixing hydrophobic nano particles with a solvent, and gradually adding a polymer to dissolve the hydrophobic nano particles under the combined action of strong stirring and ultrasound to obtain a homogeneous mixed solution;

and step two, soaking the polypropylene microporous base membrane in the hydrophobic nano particle blended polymer mixed solution prepared in the step one for 60 s-12 h, taking out, airing, and drying at the drying temperature of 60-150 ℃ for 0.5-12 h to obtain the superhydrophobic polypropylene microporous membrane.

Compared with the prior art, the invention has the beneficial effects that:

(1) by utilizing the interlacing action between the nano particles and the high polymer material, a uniform and stable super-hydrophobic layer with lower surface energy can be constructed on the surface of the polypropylene microporous membrane with low surface energy, and the contact angle of the super-hydrophobic layer is unchanged after long-time ultrasonic treatment;

(2) the surface layer has the characteristics of rough micro-morphology and low surface energy;

(3) the invention has the advantages of wide source of raw materials, low price, simple and controllable preparation process, greatly improved hydrophobic property of the membrane surface and even contact angle of more than 160 degrees.

(4) The preparation process of the super-hydrophobic membrane does not need complex membrane preparation equipment, and the membrane preparation cost is low.

(5) The membrane can be used in the fields of membrane desulfurization, deamination, decarburization, degassing, membrane distillation, membrane crystallization and the like, and meets the use requirements of various hydrophobic microporous membranes.

Drawings

FIG. 1 shows the contact angle of the modified polypropylene microporous membrane in example 1, which is 161.6 °;

FIG. 2 shows the contact angle of the modified microporous polypropylene membrane of example 2, which is 168.7 degrees;

FIG. 3-1 is a microscopic morphology of the modified polypropylene microporous membrane of example 3;

FIG. 3-2 shows the contact angle of the modified microporous polypropylene membrane of example 3, which is 158.9 °;

FIG. 4 shows the contact angle of the modified microporous polypropylene membrane of example 4, which is 157.2 degrees;

FIG. 5 shows the contact angle of the polypropylene microporous membrane after modification of example 5, wherein the contact angle is 162.2 degrees;

fig. 6 shows the contact angle of the polypropylene microporous membrane before modification, and the contact angle is 102.6 degrees.

Detailed Description

The invention utilizes the interlacing action between the hydrophobic nano material and the macromolecule long chain to construct a super-hydrophobic layer which is uniform and stable, has rough micro-appearance and low surface energy on the surface of the polypropylene microporous membrane, thereby preparing the super-hydrophobic polypropylene microporous membrane. The invention has the advantages of wide raw material source, low price, simple and controllable preparation process, no need of complex preparation equipment, greatly improved hydrophobic property of the membrane surface, contact angle even reaching more than 160 degrees, and capability of meeting the use requirements of various hydrophobic microporous membranes. The super-hydrophobic polypropylene microporous membrane prepared by the invention can be applied to the fields of membrane desulfurization, deamination, decarburization, degassing, membrane distillation, membrane crystallization and the like.

The super-hydrophobic polypropylene microporous membrane provided by the invention comprises a polypropylene microporous base membrane and a super-hydrophobic layer constructed on the surface of the polypropylene microporous base membrane, as shown in figure 3-1; the super-hydrophobic layer is prepared by blending hydrophobic nano particles with a polymer. The super-hydrophobic polypropylene microporous membrane is prepared by the following steps:

step one, mixing hydrophobic nanoparticles with a solvent, gradually adding a polymer to dissolve the mixture under the combined action of strong stirring and ultrasound to obtain a homogeneous mixed solution, wherein the mass percentages of the hydrophobic nanoparticles, the polymer and the solvent in the hydrophobic nanoparticle blended polymer are as follows: 0.2-5%/0.1-5%/90.0-99.7%, the sum of the mass percentages is 100%

The hydrophobic nano-particles are one or more of hydrophobic graphene, hydrophobic carbon nano-tubes, hydrophobic metal organic frameworks and hydrophobic silicon dioxide; the particle size of the hydrophobic nano particles is 10 nm-300 nm; the polymer is one or more of polypropylene, polyethylene, polyvinyl chloride and polyvinylidene fluoride; the solvent is one or more of cyclohexanone, xylene, tetrahydrofuran, ethyl acetate and dichloroethane.

And step two, soaking the polypropylene microporous base membrane in the hydrophobic nano particle blended polymer mixed solution prepared in the step one for 60 s-12 h, taking out, airing, and drying at the drying temperature of 60-150 ℃ for 0.5-12 h to obtain the superhydrophobic polypropylene microporous membrane.

The polypropylene microporous base membrane is in the form of one of a hollow fiber membrane, a tubular membrane and a flat membrane.

The invention will be further described with reference to the following figures and specific examples, which are not intended to limit the invention in any way.

Example 1:

ultrasonically dispersing 1g of hydrophobic graphene with the particle size of 300nm in 100ml of tetrahydrofuran, transferring the dispersed suspension to a three-neck flask with a stirring device, placing the flask in an oil bath kettle at 80 ℃, gradually adding 2g of polyvinyl chloride into the oil bath kettle, stirring the mixture strongly for 4 hours, and then ultrasonically stirring the mixture for 1 hour to obtain the hydrophobic graphene blended polyvinyl chloride coating liquid with uniformly mixed hydrophobic nano particles, high polymer materials and solvents.

And (3) soaking the polypropylene microporous membrane before modification in the hydrophobic graphene blended polyvinyl chloride coating solution for 5min, taking out and airing for 0.5h, and then drying at 100 ℃ for 1h to obtain the super-hydrophobic polypropylene microporous membrane.

Fig. 6 shows that the contact angle of the polypropylene microporous membrane before modification is 102.6 degrees, and the contact angle of the modified superhydrophobic polypropylene microporous membrane prepared in example 1 is 161.6 degrees, as shown in fig. 1.

Example 2:

ultrasonically dispersing 2g of hydrophobic carbon nano-tubes with the length of 150nm in 100ml of dimethylbenzene, transferring the dispersion suspension to a three-neck flask with a stirring device, placing the three-neck flask in an oil bath kettle at 130 ℃, gradually adding 3.5g of polypropylene into the three-neck flask, strongly stirring the mixture for 6 hours, and then ultrasonically stirring the mixture for 2 hours to obtain the hydrophobic carbon nano-tube blended polypropylene coating liquid with uniformly mixed hydrophobic nano-particles, high polymer materials and solvents. And (3) soaking the polypropylene microporous base membrane in the hydrophobic carbon nanotube blended polypropylene coating liquid for 1h, taking out and airing for 2h, and then drying at the temperature of 110 ℃ for 0.5h to obtain the super-hydrophobic polypropylene microporous membrane, wherein the contact angle of the super-hydrophobic polypropylene microporous membrane is 168.7 degrees, as shown in figure 2.

Example 3:

0.5g of hydrophobic nano-silica with the particle size of 30nm is ultrasonically dispersed in 100ml of dimethylbenzene, the dispersed suspension is transferred to a three-neck flask with a stirring device, the three-neck flask is placed in an oil bath kettle at the temperature of 80 ℃, 1g of polyvinyl chloride is gradually added into the three-neck flask, the mixture is vigorously stirred for 2 hours, and then the mixture is ultrasonically treated for 0.5 hour, so that the hydrophobic nano-silica blended polyvinyl chloride coating solution with uniformly mixed hydrophobic nano-particles, high polymer materials and solvents is obtained. Soaking the polypropylene microporous base membrane in the hydrophobic nano-silica blended polyvinyl chloride coating liquid for 4h, taking out and airing for 4h, then drying at 90 ℃ for 2h to obtain the super-hydrophobic polypropylene microporous membrane, wherein the microscopic topography of the super-hydrophobic polypropylene microporous membrane is shown in a figure 3-1, a gray arrow points to the base membrane, a white line arrow points to the super-hydrophobic layer, a black line arrow points to the nano-particles, and the contact angle of the super-hydrophobic polypropylene microporous membrane is 158.9 degrees, as shown in a figure 3-2.

Example 4:

ultrasonically dispersing 0.25g of hydrophobic nano-silica with the particle size of 30nm and 0.25g of hydrophobic graphene with the size of 50nm in 100ml of dimethylbenzene, transferring the dispersed suspension to a three-neck flask with a stirring device, placing the three-neck flask in a 130 ℃ oil bath pot, gradually adding 1g of polyethylene into the three-neck flask, stirring the mixture strongly for 1h, and then ultrasonically stirring the mixture for 0.5h to obtain the polyethylene coating liquid with uniformly mixed double-component hydrophobic nano-particles, high polymer materials and solvents. And (3) soaking the polypropylene microporous base membrane in the polyethylene coating liquid for 12h, taking out and airing for 4h, and drying at the temperature of 60 ℃ for 12h to obtain the super-hydrophobic polypropylene microporous membrane, wherein the contact angle of the super-hydrophobic polypropylene microporous membrane is 157.2 degrees, as shown in figure 4.

Example 5:

0.25g of hydrophobic nano-silica with the particle size of 100nm, 0.25g of hydrophobic graphene with the size of 200nm and 0.25g of hydrophobic metal organic framework with the particle size of 300nm are ultrasonically dispersed in 100ml of tetrahydrofuran, the dispersed suspension is transferred to a three-neck flask with a stirring device, the three-neck flask is placed in an oil bath kettle at the temperature of 80 ℃, 1g of polyvinylidene fluoride is gradually added into the three-neck flask, the mixture is intensively stirred for 1 hour and then is ultrasonically treated for 0.5 hour, and the polyvinylidene fluoride coating liquid with uniformly mixed multicomponent hydrophobic nano-particles, high polymer materials and solvents is obtained. And (3) soaking the polypropylene microporous base membrane in the polyvinylidene fluoride coating liquid for 8 hours, taking out and airing for 12 hours, and drying at the temperature of 150 ℃ for 6 hours to obtain the super-hydrophobic polypropylene microporous membrane, wherein the contact angle of the super-hydrophobic polypropylene microporous membrane is 162.2 degrees, as shown in figure 5.

The hydrophobic nano particles are one or more of hydrophobic graphene, hydrophobic carbon nano tubes, hydrophobic metal organic frameworks and hydrophobic silicon dioxide; the particle size of the hydrophobic nano particles is 10 nm-300 nm. In the preparation process, the nano-particles are uniformly mixed with a low-concentration polymer solution, soaked and dried, which is a key point for keeping stable hydrophobicity, otherwise, the nano-particles are easy to fall off, the hydrophobicity is reduced, the better the hydrophobicity of the nano-particles is, and the better the hydrophobicity of a hydrophobic film is; particularly, the hydrophobic nano particles in the invention adopt a hydrophobic carbon nano tube material, which is beneficial to improving the hydrophobic angle of a membrane material, and in a limited particle size range, relatively speaking, the smaller the particle sizes of a hydrophobic metal organic framework and hydrophobic silicon dioxide are, the larger the size of hydrophobic graphene is, the longer the length of the hydrophobic carbon nano tube is, and the better the hydrophobicity of the hydrophobic membrane is; according to the invention, the concentration of the hydrophobic nanoparticles in the hydrophobic nanoparticle blended polymer is 0.5% -2%, so that the hydrophobic property is ensured, a higher contact angle is realized, the concentration is too low, the hydrophobic stability is reduced, the concentration is too high, and the hydrophobic angle is reduced. In the preparation method, the polypropylene microporous base membrane is soaked in the mixed solution of the hydrophobic nano particle and the polymer, the reaction time is longer, the soaking is sufficient, and after the drying, the combination of the hydrophobic layer and the base membrane is more stable and firm.

Compared with the polypropylene microporous membrane before modification, the super-hydrophobic polypropylene microporous membrane obtained by modifying the polypropylene microporous membrane has the advantages that the contact angle between the super-hydrophobic polypropylene microporous membrane and water is obviously improved, the anti-wettability is obviously enhanced, the system operation stability is obviously enhanced in the application process of the super-hydrophobic polypropylene microporous membrane in the fields of desulfurization and the like, the large-scale engineering application of the membrane technology in the fields of desulfurization, deamination, decarburization, degassing, membrane distillation, membrane crystallization and the like is facilitated, the traditional industry upgrading is realized, and the quality and the consumption are reduced. Such as: in a membrane desulfurization experiment, a wetting phenomenon appears after a conventional polypropylene microporous membrane runs for 48 hours, a super-hydrophobic polypropylene microporous membrane stably runs for 150 hours, the wetting phenomenon still does not exist, and the running stability is obviously enhanced.

While the present invention has been described with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are illustrative only and not restrictive, and various modifications which do not depart from the spirit of the present invention and which are intended to be covered by the claims of the present invention may be made by those skilled in the art.