Metal-modified amino silicone rubber film, method for preparing the same, and use thereof

Abstract

The application belongs to the technical field of membrane materials, and particularly relates to a metal-modified amino silicone rubber membrane, a preparation method and application thereof. Amino silicone rubber is dissolved in a solvent containing a catalyst, a crosslinking agent is added, a metal salt solution is added, and stirring is performed to carry out a crosslinking polymerization reaction, so as to obtain a metal-modified amino silicone rubber casting solution. The casting solution is diluted and then coated on a PAN support as a separation layer, and then dried and heat-treated to obtain a metal-modified amino silicone rubber membrane. In the application, amino silicone rubber is used as a monomer, NH2-PDMS is modified by a metal, the separation performance of the membrane is further improved, the pore structure of the membrane is optimized, the metal-modified amino silicone rubber membrane has a looser network structure, the flux of the membrane and the separation selectivity of CO2 / N2 can be improved without changing the original membrane network structure, the metal material structure is optimized, the composite membrane with the best separation performance is obtained, and the application prospect is wide.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of film materials, and particularly relates to a metal-modified amino silicone rubber film and a preparation method and application thereof. BACKGROUND

[0002] The greenhouse effect caused by excessive emission of CO2 and other environmental problems need to be solved urgently, and how to control CO2 emission and efficiently capture CO2 is crucial. Compared with traditional CO2 separation technologies such as absorption and low-temperature separation, membrane separation technology has the characteristics of high efficiency, energy saving, green environmental protection, simple operation and easy scaling, and therefore, has attracted more and more attention. The core of the membrane separation technology is to develop a membrane material with high permeability and high selectivity. According to the type of the membrane material, the CO2 separation membrane material can be divided into organic membranes, inorganic membranes and organic-inorganic hybrid membranes.

[0003] Silicone rubber material has good chemical stability and excellent gas permeability due to its high-elasticity, large change of Si-O-Si bond angle and other characteristics, and is widely used in gas separation and liquid separation. The chain segment flexibility of the silicone rubber material makes it have high gas permeability, but also limits the improvement of selectivity. Compared with PDMS membrane material, NH2-PDMS contains not only similar dimethyl side groups to PDMS, but also amino groups with good affinity for CO2, which is beneficial to the selective adsorption of CO2 and the optimization of the gas separation performance of the membrane. Considering the actual industrial application, the larger the membrane flux is, the more conducive to reducing the processing cost and improving the production efficiency. Therefore, how to further enhance the permeation flux of the NH2-PDMS membrane has important practical significance. SUMMARY

[0004] In view of the problems in the background art, the application provides a metal-modified amino silicone rubber film and a preparation method thereof.

[0005] The preparation method of the metal-modified amino silicone rubber film provided by the application comprises the following steps:

[0006] (1) Dissolve the silicone rubber in n-heptane solvent containing 2-lauric acid-2-butyl tin catalyst, then add crosslinking agent 1,4-bis(triethoxysilyl) benzene (BTESB) to the mixed solution, and then add a metal salt solution dissolved in ethanol, continuously stir in a sealed glass bottle, and perform room temperature crosslinking polymerization reaction to prepare a metal-modified amino silicone rubber casting solution.

[0007] The silicone rubber is poly[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane (NH2-PDMS).

[0008] m(NH2-PDMS):m(BTESB):m(2-lauric acid-2-butyl tin) = 1:0.1-0.3:0.01-0.03.

[0009] The metal salt is: cobalt nitrate hexahydrate, nickel nitrate hexahydrate, lanthanum nitrate hexahydrate, and the mass ratio of the metal salt solution to NH2-PDMS is 0.001-0.0075:1.

[0010] The cross-linking polymerization reaction time is 10-15h, and the viscosity of the obtained silicone rubber casting solution is controlled to be 40cp-45cp.

[0011] (2) The metal-modified amino silicone rubber casting solution is coated on the PAN support as a separation layer, and after air drying at room temperature and heat treatment, the metal-modified amino silicone rubber membrane can be obtained.

[0012] The method for coating the metal-modified amino silicone rubber casting solution is a doctor blade method, the support is cut into a suitable size and placed on a clean glass plate, deionized water is added on the surface, the deionized water on the surface is wiped off with a dust-free paper, and then the casting solution is coated on the PAN support to prepare a membrane.

[0013] The average pore size of the PAN support is 25nm.

[0014] The heat treatment temperature is: 60-120℃, and the heat treatment time is: 6-10h.

[0015] The application of the metal-modified amino silicone rubber membrane prepared by the method in gas separation is specifically that the metal-modified amino silicone rubber membrane is used for the separation of CO2 / N2.

[0016] The present application has the following advantages:

[0017] The present application provides a metal-modified amino silicone rubber membrane, which uses NH2-PDMS as a monomer and BTESB as a cross-linking agent, and the NH2-PDMS material is modified by a metal, further improving the separation performance of the membrane and optimizing the pore structure of the membrane, so that the metal-modified amino silicone rubber membrane prepared has a more loose network structure, can improve the flux and CO2 / N2 separation selectivity of the membrane without changing the original membrane network structure, and by optimizing the structure of the metal material, a composite membrane material with the best separation performance is obtained.

[0018] In addition, the metal can form a coordination effect with the N atoms in the NH2-PDMS membrane, causing changes in the overall structure of the membrane and increasing the d-spacing of the membrane, thereby increasing the permeation rate of the membrane, and the metal generally has high thermal stability, and doping the metal can limit the movement of the polymer chain to a certain extent, which helps to maintain the integrity and stability of the membrane. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows.

[0020] Figure 1 The Fourier infrared spectra of PDMS, NH2-PDMS and metal modified NH2-PDMS (1-PDMS; 2-NH2-PDMS; 3-Co-NH2-PDMS; 4-Ni-NH2-PDMS; 5-La-NH2-PDMS);

[0021] Figure 2 The X-ray photoelectron spectrograms (full spectrograms) of PDMS, NH2-PDMS and metal modified NH2-PDMS materials (1-PDMS; 2-NH2-PDMS; 3-Co-NH2-PDMS; 4-Ni-NH2-PDMS; 5-La-NH2-PDMS);

[0022] Figure 3 The X-ray photoelectron spectrograms (Si2p fine spectrograms) of PDMS, NH2-PDMS and metal modified NH2-PDMS materials (1-PDMS; 2-NH2-PDMS; 3-Co-NH2-PDMS; 4-Ni-NH2-PDMS; 5-La-NH2-PDMS);

[0023] Figure 4 The X-ray photoelectron spectrograms (N1s fine spectrograms) of PDMS, NH2-PDMS and metal modified NH2-PDMS materials (1-PDMS; 2-NH2-PDMS; 3-Co-NH2-PDMS; 4-Ni-NH2-PDMS; 5-La-NH2-PDMS);

[0024] Figure 5 The X-ray photoelectron spectrograms (Co2p fine spectrograms) of PDMS, NH2-PDMS and metal modified NH2-PDMS materials (2-NH2-PDMS; 3-Co-NH2-PDMS). DETAILED DESCRIPTION

[0025] In order to make the above objectives, features and advantages of the present application more apparent and comprehensible, the specific embodiments of the present application will be described in detail below with reference to the embodiments of the present application.

[0026] The raw materials used in the present application are all commercially available in the art without special instructions.

[0027] The silicone rubbers used in the present application and their abbreviations are as follows:

[0028] Polydimethylsiloxane (PDMS) and poly[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane (NH2-PDMS).

[0029] In the present application, the metal-modified amino silicone rubber membrane is used for the separation of CO2 / N2. The membrane is placed in a membrane module, connected to a gas cylinder, and the CO2 / N2 flux and CO2 / N2 selectivity of different membranes are measured under a CO2 / N2 feed pressure of 100 kPa and a feed temperature of 25°C.

[0030] Example 1

[0031] 1) Preparation of Co-NH2-PDMS casting solution

[0032] 0.529 g of NH2-PDMS silicone rubber is dissolved in 9.9947 g of n-heptane, 0.0053 g of 2-lauryl acid-2-butyl tin catalyst is added, and then 0.0529 g of BTESB crosslinking agent is added to the mixed solution, followed by the addition of a cobalt nitrate hexahydrate solution dissolved in ethanol (the mass of cobalt nitrate hexahydrate is 0.002645 g). The crosslinking polymerization reaction is carried out in a closed glass bottle at room temperature with continuous stirring for 12 h until the appropriate viscosity (40-45 cp) is reached, thereby preparing the Co-NH2-PDMS casting solution. In this process, m(NH2-PDMS):m(BTESB):m(2-lauryl acid-2-butyl tin) = 1:0.1:0.01, and the mass ratio of cobalt nitrate hexahydrate to NH2-PDMS silicone rubber is 0.005:1.

[0033] 2) Preparation of silicone rubber membrane

[0034] In the experiment, PAN with an average pore size of 25 nm is selected as the support. The support is cut to the appropriate size (one decimeter) before being placed on a clean glass plate, and deionized water is added to the surface. The deionized water on the surface is then gently wiped off with a dust-free paper and is ready for use. The Co-NH2-PDMS casting solution is used as the separation layer and is coated on the PAN support using a doctor blade method to prepare a membrane (about 20 μm). The membrane is dried at room temperature and then placed in a 60°C oven for 6 h, thereby obtaining the Co-NH2-PDMS membrane.

[0035] Example 2

[0036] In this example, the difference from Example 1 is that the cobalt nitrate hexahydrate in step 1) is replaced with nickel nitrate hexahydrate of the same mass, thereby obtaining the membrane of this example, which is denoted as Ni-NH2-PDMS membrane.

[0037] Example 3

[0038] This embodiment differs from embodiment 1 in that step 1) is adjusted to replace cobalt nitrate hexahydrate with lanthanum nitrate hexahydrate of the same mass, thereby obtaining the membrane of this embodiment, which is denoted as La-NH2-PDMS membrane.

[0039] The composite membranes prepared in Examples 1-3 were tested for gas separation performance at a feed pressure of 100 kPa and a feed temperature of 25° C. The results are shown in Table 1.

[0040] Table 1 CO2, N2 flux and CO2 / N2 selectivity of membranes doped with different metals at a feed pressure of 100 kPa and a feed temperature of 25 °C

[0041]

[0042] It can be seen from Table 1 that when the added metals are Co, Ni, and La, the CO2 permeation rates are 4.01×10 -6 mol / (m 2 ·s·Pa)、3.68×10 -6 mol / (m 2 ·s·Pa)、3.15×10 -6 mol / (m 2 ·s·Pa), and the CO2 / N2 selectivity was 11. The addition of all three metals significantly increased the permeation rates of CO2 and N2. This is because the addition of the metals creates a coordination effect between the metals and the nitrogen atoms in the NH2-PDMS membrane, which changes the overall structure of the membrane and increases the d-spacing, thereby increasing the membrane's permeation rate.

[0043] Example 4

[0044] This example differs from Example 1 in that the metal content added in step 1 was adjusted. Specifically, a cobalt nitrate hexahydrate solution dissolved in ethanol (the mass of cobalt nitrate hexahydrate was 0.000529 g) was added, and the mass ratio of cobalt nitrate hexahydrate to NH2-PDMS silicone rubber was 0.001:1. The membrane of this example was obtained, which was designated as a 0.1 wt% Co-NH2-PDMS membrane.

[0045] Example 5

[0046] This example differs from Example 1 in that the metal content added in step 1 was adjusted. Specifically, a cobalt nitrate hexahydrate solution dissolved in ethanol (the mass of cobalt nitrate hexahydrate was 0.0013225 g) was added, and the mass ratio of cobalt nitrate hexahydrate to NH2-PDMS silicone rubber was 0.0025:1. The membrane of this example was obtained, which was designated as a 0.25 wt% Co-NH2-PDMS membrane.

[0047] Example 6

[0048] The difference between this example and Example 1 is that the content of the metal added in step 1 is adjusted, i.e. a cobalt nitrate hexahydrate solution dissolved in ethanol (the mass of the cobalt nitrate hexahydrate is 0.0039675 g) is further added, and the mass ratio of the cobalt nitrate hexahydrate to the NH2-PDMS silicone rubber is 0.0075:1. The membrane of this example is obtained, and the membrane is denoted as 0.75wt%Co-NH2-PDMS membrane.

[0049] The composite membranes prepared in Example 1 and Examples 4-6 are tested for gas separation performance under a feed pressure of 100 kPa and a feed temperature of 25°C, and the results are shown in Table 2.

[0050] Table 2 CO2and N2fluxes and CO2 / N2selectivity of membranes with different Co ratios under a feed pressure of 100 kPa and a feed temperature of 25°C

[0051]

[0052]

[0053] As can be seen from Table 2, when the added Co ratios are 0.10wt%, 0.25wt%, 0.50wt% and 0.75wt% respectively, the CO2permeation rates are 2.89x10 -6 mol / (m 2 ·s·Pa), 3.64x10 -6 mol / (m 2 ·s·Pa), 4.01x10 -6 mol / (m 2 ·s·Pa) and 3.71x10 -6 mol / (m 2 ·s·Pa), and the CO2 / N2selectivities are 11, 11, 12 and 11 respectively. With the increase of the Co ratio, the permeation rates of CO2and N2first increase and then decrease. This is because when the added Co ratio exceeds 0.50wt%, saturation is reached, and theoretically, one Co atom can be coordinated with six -NH2, so the permeation rate when the added Co ratio is increased to 0.75wt% is slightly lower than that when the added Co ratio is 0.50wt%.

[0054] Comparative Example 1

[0055] 1) Preparation of NH2-PDMS casting solution

[0056] NH2-PDMS casting solution was prepared by dissolving 0.529 g of NH2-PDMS silicone rubber in 9.9947 g of n-heptane, adding 0.0053 g of 2-lauric acid-2-butyl tin catalyst, and then adding 0.0529 g of BTESB crosslinking agent to the mixed solution. The crosslinking polymerization reaction was carried out in a closed glass bottle at room temperature with continuous stirring for 12 h until a suitable viscosity (40-45 cp) was reached. In this process, m(NH2-PDMS):m(BTESB):m(2-lauric acid-2-butyl tin) = 1:0.1:0.01.

[0057] 2) Preparation of silicone rubber membrane

[0058] PAN with an average pore size of 25 nm was selected for the experiment. The support was cut to the appropriate size (one decimeter) before use and placed on a clean glass plate. Deionized water was added to the surface, and then the deionized water on the surface was wiped off with a dust-free paper. NH2-PDMS casting solution was used as the separation layer and was coated on the PAN support using a doctor blade method to prepare a film. The film was dried at room temperature and then placed in a 60°C oven for 6 h to obtain the NH2-PDMS membrane.

[0059] The composite membranes prepared in Example 1 and Comparative Example 1 were tested for gas separation performance at a feed pressure of 100 kPa and a feed temperature of 25°C. The results are shown in Table 3.

[0060] Table 3 CO2 and N2 fluxes and CO2 / N2 selectivity of the membranes at a feed pressure of 100 kPa and a feed temperature of 25°C

[0061]

[0062] Comparative Example 2

[0063] 1) Preparation of Co-PDMS casting solution

[0064] Co-PDMS casting solution was prepared by dissolving 0.529 g of PDMS silicone rubber in 9.9947 g of n-heptane, adding 0.0053 g of 2-lauric acid-2-butyl tin catalyst, and then adding 0.0529 g of BTESB crosslinking agent to the mixed solution. The crosslinking polymerization reaction was carried out in a closed glass bottle at room temperature with continuous stirring for 12 h until a suitable viscosity (40-45 cp) was reached. In this process, m(PDMS):m(BTESB):m(2-lauric acid-2-butyl tin) = 1:0.1:0.01, and the mass ratio of cobalt nitrate hexahydrate to PDMS silicone rubber was 0.005:1.

[0065] 2) Preparation of silicone rubber membrane

[0066] The PAN support with an average pore size of 25 nm was selected for the experiment. When used, the support was cut into the appropriate size (one decimeter) and placed on a clean glass plate, and deionized water was added to the surface. The deionized water on the surface was then gently wiped off with a dust-free paper and used as is. The Co-PDMS casting solution was used as the separation layer, and a film was prepared by using a doctor blade method to coat the PAN support. The film was air-dried at room temperature, and then placed in a 60°C oven for drying for 6 h, to obtain the Co-PDMS membrane.

[0067] The composite membranes prepared in Example 1 and Comparative Example 2 were tested for gas separation performance at a feed pressure of 100 kPa and a feed temperature of 25°C, and the results are shown in Table 4.

[0068] Table 4 CO2and N2fluxes and CO2 / N2selectivity of the membranes at a feed pressure of 100 kPa and a feed temperature of 25°C

[0069]

[0070] Comparative Example 3

[0071] The difference between this comparative example and Example 1 is that the metal was introduced by the impregnation method, and the specific steps are as follows:

[0072] 0.529 g of NH2-PDMS silicone rubber was dissolved in 9.9947 g of n-heptane, 0.0053 g of 2-lauryl acid-2-butyl tin catalyst was added, and 0.0529 g of BTESB crosslinking agent was added to the mixed solution. The crosslinking polymerization reaction was carried out in a closed glass bottle at room temperature for 12 h with continuous stirring, until the appropriate viscosity (40-45 cp) was reached, to obtain the NH2-PDMS casting solution. In this process, m(NH2-PDMS):m(BTESB):m(2-lauryl acid-2-butyl tin) = 1:0.1:0.01.

[0073] The PAN support with an average pore size of 25 nm was selected for the experiment. When used, the support was cut into the appropriate size (one decimeter) and placed on a clean glass plate, and deionized water was added to the surface. The deionized water on the surface was then gently wiped off with a dust-free paper and used as is. The Co-PDMS casting solution was used as the separation layer, and a film was prepared by using a doctor blade method to coat the PAN support. The film was air-dried at room temperature, and then placed in a 60°C oven for drying for 6 h, to obtain the Co-PDMS membrane.

[0074] The composite membranes prepared in Example 1 and Comparative Example 3 were tested for gas separation performance at a feed pressure of 100 kPa and a feed temperature of 25℃, and the results are shown in Table 5.

[0075] Table 5 CO2, N2fluxes and CO2 / N2selectivity of the membranes at a feed pressure of 100 kPa and a feed temperature of 25℃

[0076]

[0077]

[0078] Comparative Example 4

[0079] The only difference between this comparative example and Example 1 is that 1,2-bis(triethoxysilyl)methane (BTESM) was used as the crosslinking agent, and the other steps were performed according to Example 1 to obtain the membrane of this comparative example.

[0080] The composite membranes prepared in Example 1 and Comparative Example 4 were tested for gas separation performance at a feed pressure of 100 kPa and a feed temperature of 25℃, and the results are shown in Table 6.

[0081] Table 6 CO2, N2fluxes and CO2 / N2selectivity of the membranes at a feed pressure of 100 kPa and a feed temperature of 25℃

[0082]

[0083] In summary, the present application provides a method for preparing a metal-modified amino silicone rubber membrane. The amino material used in the present application has an affinity for CO2, which is beneficial for selective adsorption of CO2 and thus optimizes the gas separation performance of the membrane. Furthermore, the flux of the membrane is further improved by doping a metal material, which can significantly improve the production efficiency and reduce the cost in industrial applications.

[0084] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and all such modifications or replacements should be covered in the scope of the claims of the present application.

Claims

1. A method for preparing a metal-modified aminosilicone rubber film, characterized in that: The preparation method comprises the following steps: (1) Dissolve the amino silicone rubber in a solvent containing a catalyst, add the crosslinking agent 1,4-bis(triethoxysilyl)benzene BTESB, and then add the metal salt solution dissolved in ethanol. Place the mixture in a sealed glass bottle and stir continuously to perform a crosslinking polymerization reaction to obtain a metal-modified amino silicone rubber casting solution. Amino silicone rubber is: poly[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane NH2-PDMS; The metal salts are: cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and lanthanum nitrate hexahydrate; (2) The metal-modified amino silicone rubber casting liquid is coated on the PAN support as a separation layer, dried at room temperature, and then heat-treated to obtain the metal-modified amino silicone rubber membrane.

2. The method for preparing the metal-modified aminosilicone rubber film according to claim 1, wherein: The structural formula of the amino silicone rubber is shown below: 。 3. The method for preparing the metal-modified aminosilicone rubber film according to claim 1, wherein: The catalyst is 2-butyltin 2-laurate, and the solvent is n-heptane; the mass ratio of the poly[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane NH2-PDMS, 1,4-bis(triethoxysilyl)benzene and 2-butyltin 2-laurate is 1:0.1-0.3:0.01-0.

03.

4. The method for preparing the metal-modified aminosilicone rubber film according to claim 1, wherein: The mass ratio of the metal salt solution to poly[3-((2-aminoethyl)amino)propyl]methyl(dimethyl)siloxane is 0.001-0.0075:1, and the viscosity of the obtained metal-modified aminosilicone rubber casting liquid is 40 cp-45 cp.

5. The method for preparing the metal-modified aminosilicone rubber film according to claim 1, wherein: The cross-linking polymerization reaction is: reacting at room temperature for 10-15 hours.

6. The method for preparing the metal-modified aminosilicone rubber film according to claim 1, wherein: The method of coating the casting liquid is: cut the support PAN and place it on a clean glass plate, add deionized water on the surface, then gently wipe off the deionized water on the surface with dust-free paper, and then scrape the metal-modified amino silicone rubber casting liquid on the PAN support to prepare a film.

7. The method for preparing the metal-modified aminosilicone rubber film according to claim 1, wherein: The average pore diameter of the PAN support is 25 nm.

8. The method for preparing the metal-modified aminosilicone rubber film according to claim 1, wherein: The heat treatment temperature is 60-120° C., and the heat treatment time is 6-10 hours.

9. A metal-modified amino silicone rubber membrane prepared by the method according to any one of claims 1 to 8.

10. An application of a metal-modified aminosilicone rubber film prepared by the method according to any one of claims 1 to 8, characterized in that: The metal-modified aminosilicone rubber membrane is used for CO2 / N2 separation.

Images