Porous membrane composite material as well as preparation method and application thereof

Abstract

The invention relates to the field of material science, in particular to a porous membrane composite material with excellent waterproof and moisture permeable performance and good flexibility, a preparation method of the porous membrane composite material and application of the composite material in related fields. According to the preparation method disclosed by the invention, by adopting a technology of coating SiO nanoparticles with POSS (polyhedral oligomeric silsesquioxane), the problem that the flexibility is reduced due to a traditional nano silicon dioxide doped polyurethane porous membrane is effectively solved.

Description

Technical field:

[0001] The present invention relates to the field of material science, and in particular to a porous membrane composite material having excellent waterproof and moisture permeability and maintaining good flexibility, a preparation method thereof, and applications of the composite material in related fields. Background technology:

[0002] Porous membrane is a thin film material with a microporous structure. Due to its unique pore structure and surface properties, it is widely used in separation, filtration, breathability, waterproofing and other fields. The performance of porous membranes mainly depends on the size, shape, distribution of its pores and the properties of the membrane material itself. With the advancement of science and technology and the continuous improvement of application needs, the performance requirements for porous membranes are becoming increasingly stringent, especially in terms of waterproof and breathable performance.

[0003] In many applications, such as outdoor clothing, building curtain walls, and automotive interiors, porous membranes are required to have good waterproof and breathable properties. Waterproof performance requires that the membrane material can effectively block the penetration of water, while breathable performance requires that the membrane material allow water vapor to pass through to keep the interior dry and comfortable. In order to meet this demand, people have adopted a variety of methods to modify porous membranes, among which the doping of nanomaterials is an effective method. Nano-silica is widely used in the modification of polyurethane porous membranes due to its unique surface properties and nano-size effect to improve its waterproof and breathable properties.

[0004] Although the addition of nano-silica can significantly improve the waterproof and breathable properties of polyurethane porous membranes, it also brings some problems that cannot be ignored. First, the rigid structure of nano-silica greatly reduces the flexibility of the porous membrane, which is particularly prominent in applications where the membrane material needs to have certain bending or stretching properties. The membrane material is prone to defects during application, affecting its service life and reliability. Secondly, the compatibility between nano-silica and the polyurethane matrix is ​​poor, the interfacial bonding force is weak, and phase separation is prone to occur. This phase separation not only affects the overall performance of the membrane material, but may also cause problems such as stratification or peeling of the membrane during use, further reducing the stability and durability of the membrane. Therefore, how to solve the problems of reduced flexibility and poor bonding while maintaining the improved waterproof and breathable performance brought about by nano-silica modification has become a technical problem that needs to be solved urgently. Summary of the invention:

[0005] The object of the present invention is to provide a porous membrane composite material and a preparation method thereof, wherein the composite material has excellent waterproof and moisture permeability and maintains good flexibility.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a porous membrane composite material comprises the following steps:

[0008] a) Preparation of POSS-coated SiO 2 Nanoparticles: POSS was dissolved in an organic solvent to form a solution, and then SiO 2 The nanoparticles were dispersed in the solution, the solvent was evaporated after stirring and vacuum dried to obtain POSS-coated SiO 2 Nanoparticles;

[0009] b) heating the polyurethane prepolymer to a flowable state, adding the POSS coated SiO 2 Nanoparticles, chain extenders and catalysts are mixed evenly to perform in-situ polymerization reaction;

[0010] c) preparing the mixed solution into a fiber membrane through a spinning process;

[0011] d) peeling the porous membrane from the receiving device to obtain a polyurethane porous membrane.

[0012] Preferably, the POSS is a cage-type polysilsesquioxane having at least one reactive functional group selected from hydroxyl, amino, epoxy, methacryloxy or chloropropyl.

[0013] Preferably, the SiO 2 The particle size of nanoparticles is 10nm to 100nm, and the specific surface area is 50m 2 / g to 500m 2 / g; POSS and SiO 2 The mass ratio of the nanoparticles is 1:1 to 1:10.

[0014] Preferably, the organic solvent is selected from ethanol and acetone, and the stirring is mechanical stirring or ultrasonic stirring.

[0015] Preferably, the number average molecular weight of the polyurethane prepolymer is 1000 to 10000, and the isocyanate group content is 1% to 10%.

[0016] Preferably, the chain extender is a diol or a diamine, the catalyst is an organic tin compound or a tertiary amine; the POSS coated SiO 2 The nanoparticles account for 2-6% of the mass of the polyurethane prepolymer, the chain extender accounts for 1-7% of the mass of the polyurethane prepolymer, and the catalyst accounts for 0.2-0.4% of the mass of the polyurethane prepolymer.

[0017] The present invention also provides a porous membrane composite material, which is prepared by the above-mentioned preparation method, and the porous membrane composite material comprises a polyurethane matrix and POSS-coated SiO2 with amino groups dispersed therein. 2 Nanoparticles.

[0018] Preferably, the porous membrane composite material further comprises a functional layer composited with one side or both sides of the polyurethane porous membrane.

[0019] Preferably, the functional layer includes at least one of an antibacterial layer, a thermal insulation layer, an anti-ultraviolet layer, an antistatic layer, a waterproof layer, a breathable layer, a reinforcing layer or a protective layer, and is compounded by coating, hot pressing, adhesive bonding or laminating.

[0020] The porous membrane composite material provided by the present invention is used in waterproof and breathable clothing, shoes and boots, tents, building waterproof and breathable membranes or medical protective equipment.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] First, the present invention adopts POSS (cage-type polysilsesquioxane) to coat SiO 2 Nanoparticle technology effectively solves the problem of reduced flexibility caused by traditional nano-silica doped polyurethane porous membranes. The flexible shell of POSS acts as a buffer layer, wrapping the rigid SiO 2 Nanoparticles significantly reduce SiO 2 Adverse effects on the rigidity of the polyurethane matrix.

[0023] Secondly, the unique hydrophobic structure of POSS provides an additional waterproof barrier for the porous membrane, effectively improving the waterproof performance of the membrane. At the same time, the nanometer size of POSS and its uniform dispersion in the porous membrane help to form a more refined and uniform microporous structure inside the membrane. These micropores not only maintain the good air permeability of the membrane, but also further optimize the moisture permeability by precisely controlling the pore size, achieving a perfect balance between waterproofness and moisture permeability, and are particularly suitable for clothing, building exterior walls, medical protection and other fields that require efficient waterproof and breathable functions.

[0024] In addition, the present invention selects POSS materials with amino groups or hydroxy groups, which enhances the solubility of POSS in polar solvents, allowing POSS to be more evenly dispersed in the solvent and effectively coating SiO 2 On the other hand, hydroxyl and amino groups can react chemically with isocyanate groups in polyurethane prepolymers to form strong chemical bonds, which significantly improves the compatibility and interfacial bonding between POSS and polyurethane matrix, improves the overall stability of the material, and effectively prevents particle agglomeration and phase separation, thereby extending the service life and performance durability of the porous membrane composite material. Description of the drawings:

[0025] Figure 1: SEM photos of the porous membrane composite materials prepared in Example 1 and Example 2 (a-Example 1, b-Example 2). Specific implementation method:

[0026] Example 1

[0027] A method for preparing a porous membrane composite material comprises the following steps:

[0028] a) Preparation of POSS-coated SiO 2 Nanoparticles:

[0029] A cage-type polysilsesquioxane (POSS) with a hydroxyl functional group grafting rate of 12% was dissolved in ethanol to form a solution with a mass concentration of 10%. 2 / g SiO 2 Nanoparticles are dispersed in the above solution, wherein POSS and SiO 2 The mass ratio of nanoparticles was 1:3.5; mechanical stirring was performed for 2 hours. The solvent was evaporated and vacuum dried to obtain POSS-coated SiO 2 Nanoparticles.

[0030] b) Preparation of polyurethane mixed solution:

[0031] Heat the polyurethane prepolymer with a number average molecular weight of 5000 and an isocyanate group content of 5% to a flowable state. Add the amino-containing POSS-coated SiO 2 Nanoparticles (accounting for 5% of the weight of the polyurethane prepolymer), ethylene glycol chain extender (accounting for 5% of the weight of the polyurethane prepolymer) and dibutyltin dilaurate catalyst (accounting for 0.3% of the weight of the polyurethane prepolymer) are mixed uniformly.

[0032] c) preparing the mixed solution into a fiber membrane through a spinning process;

[0033] d) peeling the fiber membrane from the receiving device to obtain a porous membrane composite material (the electron microscope photo of which is shown in FIG. Figure 1 a).

[0034] Example 2

[0035] The difference between Example 2 and Example 1 is that POSS with an amino functional group grafting rate of 13% is dissolved in ethanol. The electron microscope photo of the porous membrane composite material prepared in this example is as follows: Figure 1 As shown in b.

[0036] Comparative Example 1

[0037] The difference between Comparative Example 1 and Example 1 is that SiO 2 Nanoparticles are wrapped with POSS materials and SiO 2The nanoparticles are added to the polyurethane prepolymer.

[0038] Comparative Example 2

[0039] The difference between Comparative Example 2 and Example 1 is that SiO 2 The nanoparticles were coated with POSS material, and the same amount of SiO 2 The nanoparticles and POSS were simply mixed and then added to the polyurethane prepolymer.

[0040] Comparative Example 3

[0041] The difference between Comparative Example 2 and Example 1 is that POSS without grafted hydroxyl groups is used to graft SiO 2 Nanoparticles are wrapped with POSS materials.

[0042] The porous membranes of the above-mentioned embodiments and comparative examples were characterized, and the characterization contents included the following:

[0043] Characterization content and parameters

[0044] (1) Characterization parameters: Water Entry Pressure (WEP)

[0045] Characterization conditions: According to AATCC 127 standard, use a hydrostatic pressure tester with a test pressure range of 0-5000Pa.

[0046] Unit: Pa

[0047] (2) Characterization parameters: Water Vapor Transmission Rate (WVTR)

[0048] Characterization conditions: According to ASTM E96 standard, using the permeable cup method, the test temperature is 23±2℃, and the relative humidity is 50±5%.

[0049] Unit: g / (m 2 24h)

[0050] (3) Characterization parameters: Elongation at Break

[0051] Characterization conditions: According to ASTM D638 standard, a universal material testing machine was used with a tensile rate of 50 mm / min.

[0052] unit:%

[0053] (4) Characterization parameters: Tensile Strength

[0054] Characterization conditions: According to ASTM D638 standard, a universal material testing machine was used with a tensile rate of 50 mm / min.

[0055] Unit: MPa.

[0056] Table 1 Characterization data of different embodiments and comparative examples

[0057]

[0058] Based on the above data, it can be seen that the polyurethane porous membrane composite material prepared by the method of the present invention has good waterproof and moisture permeability and good mechanical properties, and has high application potential.

[0059] However, what is described above is only a specific embodiment of the present invention, and should not be used to limit the scope of implementation of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for preparing a porous membrane composite material, characterized in that: The following steps are involved: a) preparing POSS-coated SiO2 nanoparticles: dissolving POSS in an organic solvent to form a solution, then dispersing SiO2 nanoparticles in the solution, stirring to evaporate the solvent and performing vacuum drying to obtain POSS-coated SiO2 nanoparticles; b) heating the polyurethane prepolymer to a flowable state, adding the POSS-coated SiO2 nanoparticles with amino groups, a chain extender and a catalyst, and mixing them uniformly to carry out an in-situ polymerization reaction; c) preparing the mixed solution into a fiber membrane through a spinning process; d) peeling the fiber membrane from the receiving device to obtain a porous membrane composite material.

2. The preparation method according to claim 1, characterized in that The POSS is a cage-type polysilsesquioxane having at least one reactive functional group selected from hydroxyl or amino, wherein the grafting rate of the reactive functional group is 5%-30%.

3. The preparation method according to claim 1, characterized in that The particle size of the SiO2 nanoparticles is 10nm to 100nm, and the specific surface area is 50m² / g to 500m² / g; the mass ratio of POSS to SiO2 nanoparticles is 1:1 to 1:

10.

4. The preparation method according to claim 1, characterized in that: The organic solvent is selected from ethanol and acetone, and the stirring is mechanical stirring or ultrasonic stirring.

5. The preparation method according to claim 1, characterized in that: The number average molecular weight of the polyurethane prepolymer is 1000 to 10000, and the isocyanate group content is 1% to 10%.

6. The preparation method according to claim 1, characterized in that: The chain extender is a diol or a diamine, and the catalyst is an organic tin compound or a tertiary amine; the POSS-coated SiO2 nanoparticles account for 2-6% of the mass of the polyurethane prepolymer, the chain extender accounts for 1-7% of the mass of the polyurethane prepolymer, and the catalyst accounts for 0.2-0.4% of the mass of the polyurethane prepolymer.

7. A porous membrane composite material, characterized in that: The porous membrane composite material is prepared by the preparation method described in any one of claims 1 to 6, and comprises a polyurethane matrix and POSS-coated SiO2 nanoparticles with amino groups dispersed therein.

8. The porous membrane composite material according to claim 7, characterized in that: The porous membrane composite material further comprises a functional layer composited with one side or both sides of the polyurethane porous membrane.

9. The porous membrane composite material according to claim 8, characterized in that: The functional layer comprises at least one of an antibacterial layer, a heat-insulating layer, an anti-ultraviolet layer, an antistatic layer, a waterproof layer, a breathable layer, a reinforcing layer or a protective layer, and is compounded by coating, hot pressing, gluing or laminating.

10. Use of the porous membrane composite material according to claim 7 in waterproof and breathable clothing, shoes and boots, tents, building waterproof and breathable membranes or medical protective equipment.

Images