CN102389754A - Mesoporous macromolecule/silicon oxide nanocomposite with layered channel structure and preparation method thereof - Google Patents

Abstract

A mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered pore structure, which uses PDMS-PEO and P123 as a mixed structure-directing agent, and a phenolic resin prepolymer as a carbon source precursor, mixed and reacted to obtain The As-made intermediate is obtained by roasting; the As-made intermediate has three diffraction peaks with a q value ratio of 1:2:3 in its small-angle X-ray scattering (SAXS) pattern. The thermal stability range of the layered structure of the nanocomposite material of the present invention is 300~380°C, the layer distance is in the range of 8~15nm, and the specific surface area, pore volume and pore diameter are respectively 500~900m ² /g, 0.40~0.58cm ³ /g and 4.5~5.6nm. The nanocomposite material of the invention is particularly suitable for the fields of low dielectric constant coating, membrane separation, sensor, optical material and the like. At the same time, the preparation method of the present invention does not need to introduce expensive silane reagents, and also avoids the traditional sol-gel process, greatly simplifies the preparation process of mesoporous polymer/silicon oxide nanocomposites, and opens up a new economical, reasonable and feasible method. A synthetic route to a highly operable mesoporous polymer/silica nanocomposite.

Description

A mesoporous polymer/silicon oxide nanocomposite material with layered pore structure and preparation method thereof

technical field

The invention belongs to the technical field of new nanomaterials, in particular to a mesoporous nanocomposite material with a one-dimensional layered pore structure and a preparation method thereof, in particular to a mesoporous polymer/silicon oxide with a one-dimensional layered pore structure Nanocomposites and methods for their preparation.

Background technique

Organic/inorganic nanocomposites not only have the characteristics of flexibility, hydrophobicity and easy functionalization of organic components, but also have high thermal stability and mechanical strength of inorganic components. For mesoporous nanocomposites, not only have excellent characteristics such as uniform pore size, orderly arrangement, and continuously adjustable pore diameter in the range of 2-50nm, but also have unique nano-space effects, so they are used in catalysis, adsorption, separation, Optoelectronic devices and electrode materials for supercapacitors have important potential applications in many fields.

Mesoporous polymer/silica nanocomposite is an important mesoporous nanocomposite material, which has better thermal, electrical conductivity, mechanical and chemical properties than single mesoporous polymer or mesoporous silica material. At the same time, the silicon oxide component in the system can effectively overcome the shortcomings of severe skeleton shrinkage, small pore size, and low specific surface area during the carbonization process of pure organic systems.

At present, the synthesis methods of mesoporous polymer/silica nanocomposites mainly include surface functionalization of mesoporous silica, post-grafting method and ternary co-assembly method. The surface functionalization method of mesoporous silica is to use silicon source containing organic functional groups or special surfactant to synthesize surface functionalized mesoporous organic silica. In this method, silicon reagent and surfactant raw materials are expensive and difficult to synthesize. It is conducive to mass production; the post-grafting method is to fill the mesoporous silica material with polymer or carbon. The research group of Professor Zhao Dongyuan of the Advanced Materials Laboratory first reported in 2006 that the mesoporous polymer/silicon oxide was first synthesized by ternary co-assembly of a commercial triblock copolymer, tetraethyl orthosilicate and phenolic resin prepolymer. Nanocomposite materials, this method overcomes the shortcomings of the first two methods, but only mesoporous polymer/silicon oxide nanocomposites with a two-dimensional hexagonal p6m structure can be obtained by this method. However, mesoporous polymer/silica nanocomposites with a one-dimensional layered channel structure have not been reported in the literature so far.

Silicon-containing surfactant is a new type of surfactant developed along with new silicone materials. It has excellent surface activity in both water and non-aqueous systems, and can reduce the surface tension to about 20 mN/m. The surface also has good wetting and spreading properties, as well as good thermal stability and physiological safety. Block copolymer polydimethylsiloxane-polyoxyethylene (PDMS-PEO) is a new type of silicone surfactant, which is composed of polysiloxane segments and polyether segments with very different properties connected by chemical bonds. made. Among them, polysiloxane is a silicon-containing organic compound. The alternating silicon structure endows it with many excellent properties, such as low surface tension, excellent viscosity-temperature performance, flexibility and spreading on polar surfaces, and good hydrophobicity. and suitable for use in a wide temperature range; the hydrophilic polyether segment endows polysiloxane with water solubility, making it not only have the high and low temperature resistance, anti-aging, and low surface tension of traditional polysiloxane And other excellent properties, but also has lubricity, softness, good spreadability and emulsification stability. In addition, PDMS-PEO block copolymers also have biocompatibility, good adaptability and low glass transition temperature.

So far, although there have been many reports on the preparation of ordered mesoporous materials by the combination of cationic/nonionic, cationic/anionic and nonionic/nonionic surfactants. However, there are few reports on the preparation of highly ordered mesoporous polymer/silica nanocomposites using PDMS-PEO as a co-template agent.

Contents of the invention

The purpose of the present invention is to propose a mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered pore structure, which has broad application prospects in the fields of adsorption, separation and catalysis.

Another object of the present invention is to provide a method for preparing the above-mentioned nanocomposite material.

The purpose of the present invention is achieved through the following technical measures:

A mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered pore structure, characterized in that it is made of two-block polymer polydimethylsiloxane-polyoxyethylene (PDMS-PEO) and The tri-block polymer polyoxyethylene-polyoxypropylene-polyoxyethylene (PEO-PPO-PEO, P123) is the mixed structure directing agent, and the phenolic resin prepolymer is the carbon source precursor, which is mixed and reacted to obtain As-made The intermediate is obtained by roasting; the As-made intermediate has three diffraction peaks with a q value ratio of 1:2:3 in its small-angle X-ray scattering (SAXS) pattern.

The above-mentioned As-made intermediate has a small-angle X-ray scattering curve as shown in a in Figure 1.

The nitrogen adsorption/desorption isotherm of the mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered pore structure has a triangular hysteresis loop.

The method for preparing the above-mentioned mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered channel structure is characterized in that: the two-block polymer polydimethylsiloxane-polyoxyethylene (PDMS-PEO) and Tri-block polymer polyoxyethylene-polyoxypropylene-polyoxyethylene (PEO-PPO-PEO, P123) solution and phenolic resin prepolymer solution are mixed, dried and reacted, and then roasted to obtain a one-dimensional layered channel. Mesoporous macromolecule/silicon oxide nanocomposite material; the drying time is 20-30 hours, and the temperature is 80-100°C.

The solution of above-mentioned PDMS-PEO and P123 is to make by dissolving PDMS-PEO and P123 in solvent, and above-mentioned phenolic resin prepolymer solution is to make by dissolving phenolic resin prepolymer in solvent; Described solvent can be toluene, Anhydrous ethanol, THF (tetrahydrofuran), etc., most preferably use THF as the solvent.

The PDMS-PEO block copolymer of the present invention is preferably PDMS-PEO of Mw = ₃₀₁₂ , DMS ₃₂ -EO ₂₀ ; polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO- PEO), its M _w = 5800, EO ₂₀ -PO ₇₀ -EO ₂₀ , trade name P123; all are commercially available products.

The above-mentioned carbon source precursor phenolic resin prepolymer Resol has a molecular weight of 400 < M _w < 500, and its network crosslinking structure is as follows:

Schematic diagram of the structure of phenolic resin

The preparation of the phenolic resin prepolymer solution of the present invention: melt 0.61g phenol at 40-42°C, add 0.13g 20wt% NaOH aqueous solution at this temperature and stir for 10 min, add 1.05g 37wt% formaldehyde aqueous solution, and heat up to 70 React at ~75°C for 1 hour, cool down to room temperature, adjust the pH of the solution to 7.0 with 0.6mol/L HCl solution, and dehydrate under vacuum and decompression for 1~2 hours below 50°C; dissolve the viscous liquid obtained in THF to make 20 The THF solution of wt% phenolic resin prepolymer is ready for use.

The above-mentioned calcination, preferably, is to calcine the above-mentioned As-made intermediate at 300-400°C for 2-4 hours to obtain a mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered channel structure.

Further preferably, the mass percent concentration of the THF solution of the above-mentioned phenolic resin prepolymer is 15 to 40wt%, preferably 20wt%; in the THF solution of PDMS-PEO and P123, the mass percent concentration of PDMS-PEO and P123 2~5wt%, preferably 3.2wt% by mass.

The mass ratio of the template agents PDMS-PEO, P123 and the carbon source precursor Resol is (0.8-1.1): (0.8-1.1): (2.5-3.5); preferably, the mass ratio is 1:1:3.

Specifically, the preparation method of the above-mentioned mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered channel structure is prepared by the solvent evaporation-induced self-assembly (EISA) method, and the specific steps are as follows:

1. Dissolve P123 and PDMS-PEO in THF, stir at 38~45°C for 8~15 min to obtain a uniform and transparent solution, then add the THF solution of phenolic resin prepolymer Resol, and stir for 0.3~0.7 h to obtain a uniform solution; The mass ratio of the above substances is PDMS-PEO:P123:Resol=0.8~1.1:0.8~1.1:2.5~3.5, the preferred mass ratio is PDMS-PEO:P123:Resol=1:1:3; phenolic resin prepolymer The mass percent concentration of THF solution is 15~40wt%, preferably 20wt%, in the THF solution of PDMS-PEO and P123, the mass percent concentration of PDMS-PEO and P123 is 2~5wt%, preferably the mass percent content Transfer the above solution to a petri dish, volatilize at room temperature for 5-8 hours, and then place the petri dish in an oven at 100°C for 24 hours to obtain a transparent orange-yellow film material. Scrape the above materials from the petri dish, grind them into powder, and get As-made samples;

2. Put the above-mentioned As-made sample in a tube furnace for roasting under the protection of nitrogen gas, and roast at 300~400°C for 2~4h to obtain a mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered channel structure. The heating rate is 5°C/min.

More specifically, the preparation method of the above-mentioned mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered channel structure:

1. Dissolve 0.5 g P123 and 0.5 g PDMS-PEO in 30.0 g tetrahydrofuran (THF), and stir at 40°C for 10 min to obtain a uniform and transparent solution. Then add 7.5g THF solution of 20 wt % phenolic resin prepolymer ( M _w <500), and stir for 0.5h to obtain a homogeneous solution. Transfer the above solution to a petri dish, volatilize at room temperature for 5-8 h, and then place the petri dish in an oven at 100°C for 24 h to obtain a transparent orange-yellow film material. The above materials were scraped off the petri dish and ground into powder to obtain As-made samples.

2. Put the As-made sample in a tube furnace and roast it under the protection of nitrogen gas at 350°C for 3 hours to prepare a mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered channel structure. The heating rate is 5°C/ min. The obtained mesoporous polymer/silicon oxide nanocomposite sample is marked as MP-PS-350N.

According to the adjustment of various material types, dosage ratios, process parameters, etc. in the present invention, the prepared mesoporous polymer/silicon oxide nanocomposites with a one-dimensional layered pore structure have different order degrees and skeleton shrinkage. different.

The present invention has following beneficial effect:

1. The thermal stability range of the layered structure of the mesoporous polymer/silicon oxide nanocomposite material with a one-dimensional layered channel structure in the present invention is 300~380°C, the interlayer distance is in the range of 8~15nm, the specific surface area, pore volume and pore size are 500~900 m ² /g, 0.40~0.58 cm ³ /g and 4.5~5.6 nm, respectively. The mesoporous macromolecule/silicon oxide nanocomposite material with one-dimensional layered pore structure is especially suitable for the fields of low dielectric constant coating, membrane separation, sensor, optical material and the like.

2. The hydrophobicity of the PDMS segment in the PDMS-PEO block copolymer is very strong. When compounded with P123, the hydrophobic core of P123 can be significantly increased, thereby effectively increasing the pore size of the obtained mesoporous material; on the other hand, PDMS-PEO can also be used as a silicon source. In the process of high-temperature calcination of the formed mesoporous material, the inorganic PDMS chain segment is directly converted into a rigid component of silicon oxide, which effectively overcomes the severe contraction of the skeleton during the carbonization process of the pure organic system. , small pore size, low specific surface area and other disadvantages; thus, silicon oxide can be introduced into the mesoporous carbon material system through a one-step method without introducing expensive silane reagents, and avoiding the traditional sol-gel process, which greatly simplifies The preparation process of the mesoporous polymer/silicon oxide nanocomposite material, thus opening up a new economical, reasonable and operable mesoporous polymer/silicon oxide nanocomposite material synthesis route. The prepared mesoporous polymer/silica nanocomposite has a stable layered pore structure, large pore size and specific surface area, and has broad application prospects in the fields of low dielectric constant coatings, membrane separation, sensors, optical materials, etc. .

Description of drawings

Figure 1 is the small-angle X-ray scattering (SAXS) pattern of layered mesoporous polymer/silicon oxide nanocomposite samples: (a) As-made samples, (b) samples calcined at 350°C under nitrogen atmosphere (MP-CS -350N);

Figure 2 is a transmission electron microscope (TEM) image of the layered mesoporous polymer/silicon oxide nanocomposite sample MP-CS-350N;

Figure 3 shows the nitrogen adsorption/desorption isotherm (A) and pore size distribution curve (B) of the layered mesoporous polymer/silicon oxide nanocomposite MP-CS-350N sample.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings, but the following description is not to limit the present invention, any deformation and change of the present invention, as long as they do not depart from the spirit of the present invention, all should belong to the definition of the appended claims of the present invention range.

The synthesis of embodiment 1 phenolic resin prepolymer

Melt 0.61g phenol at 40-42°C, add 0.13g 20 wt % NaOH aqueous solution at this temperature and stir for 10 min, add 1.05 g 37wt% formaldehyde aqueous solution, raise the temperature to 70-75°C for 1 hour, cool down to room temperature, and use 0.6 mol/L HCl solution to adjust the pH value of the solution to 7.0, and vacuum dehydration for 1 to 2 hours below 50°C. The resulting viscous liquid was dissolved in THF to prepare a 20 wt% solution for later use.

The preparation of embodiment 2 As-made samples

Dissolve 0.5 g P123 and 0.5 g PDMS-PEO in 30.0 g tetrahydrofuran (THF) and stir at 40 °C for 10 min to obtain a uniform and transparent solution. Then 7.5 g of 20 wt % phenolic resin prepolymer ( M _w <500) in THF solution was added and stirred for 0.5 h to obtain a homogeneous solution. Transfer the above solution to a petri dish, volatilize at room temperature for 5-8 h, and then place the petri dish in an oven at 100°C for 24 h to obtain a transparent orange-yellow film material. The above materials were scraped off the petri dish and ground into powder to obtain As-made samples.

The triblock copolymer P123 ( M _w =5800, EO ₂₀ -PO ₇₀ -EO ₂₀ ) in this example was purchased from Aldrich, and PDMS-PEO ( M _w =3012, DMS ₃₂ -EO ₂₀ ) was purchased from Shenzhen Mindray Seoul Chemical Technology Co., Ltd., and other reagents were purchased from Shanghai Chemical Reagent Company, and all reagents were not further processed before use.

Example 3 Preparation of Mesoporous Polymer/Silicon Oxide Nanocomposite with One-Dimensional Layered Pore Structure

The As-made sample was placed in a tube furnace for 3 h at 350 °C under the protection of nitrogen gas, and the heating rate was 5 °C/min. The obtained mesoporous polymer/silicon oxide nanocomposite sample is marked as MP-PS-350N.

Example 4 The small-angle X-ray scattering (SAXS) measurement was carried out on the sample obtained above by using the Nanostar U small-angle X-ray scattering instrument (CuKα) from Bruker, Germany. The tube pressure was 40 kV, the tube flow was 35 mA, and the recording time was 30 min. The resulting SAXS is shown in Figure 1. It can be seen from Figure 1(a) that the SAXS spectrum of the As-made sample has three clear diffraction peaks at 0.52, 0.99 and 1.54 nm ⁻¹ , and the q value ratio of these three diffraction peaks is 1:2: 3, The diffraction peaks of crystal planes are referred to as layered mesoporous results. After roasting under the protection of nitrogen at 350°C, two obvious diffraction peaks can also be observed in the SAXS spectrum of the obtained sample MP-PS-350N, and the third diffraction peak is relatively weak. By calculating the q value ratio of the three diffraction peaks is also 1:2:3. This shows that the mesoporous structure still maintains the layered structure after firing at 350 °C.

Example 5 The structure of the sample MP-PS-350N obtained above was characterized by using a Japanese JEOL JEM2011 high-resolution transmission electron microscope (TEM), with an accelerating voltage of 200 kV. The results obtained are shown in Figure 2. It can be seen from Figure 2 that the sample MP-PS-350N has an obvious layered mesoporous structure. The black area in the figure is the _SiO2 component, and the bright area is the interlayer gap formed after the surfactant is removed. The interlayer spacing is 10.5 nm.

Example 6 Micromeritics Tristar 3000 adsorption instrument was used to test the nitrogen adsorption/desorption performance of the sample MP-PS-350N obtained above. Nitrogen adsorption/desorption isotherms were obtained at 77 K. Before the test, the samples were pre-degassed at 200°C for not less than 6 h under vacuum conditions. The specific surface area ( S _BET ) of the sample is calculated by the BET method, based on the adsorption data in the range of relative pressure 0.04-0.2; the pore volume ( V _t ) and pore diameter ( D ) are calculated by the BJH model from the isotherm adsorption branch, where the pore volume Calculated with the adsorption capacity at relative pressure P/P0=0.992. The nitrogen adsorption/desorption isotherm (A) and pore size distribution curve (B) of MP-PS-350N are shown in Fig. 3. It can be seen from Figure 3(A) that an obvious broad triangular hysteresis loop appears in the relative pressure range of 0.4-0.8, which is the adsorption feature of the layered mesoporous structure, which further proves that the synthesized sample has a layered structure. The specific surface area, pore volume and pore diameter of the obtained mesoporous layered material MP-PS-350N are 645 m ² /g, 0.49 cm ³ /g and 4.9 nm, respectively.

Claims (10)

1. mesoporous polymer/monox nanometer the composite of a tool one dimension stratiform pore passage structure; It is characterized in that: it is to adopt bi-block copolymer dimethyl silicone polymer-polyoxyethylene (PDMS-PEO) and triblock polymer polyoxyethylene-poly-oxypropylene polyoxyethylene (PEO-PPO-PEO; P123) be the mixed structure directed agents; The phenolic resins performed polymer is the carbon source precursor body, mix, react the As-made intermediate, make through roasting again; Said As-made intermediate in its small angle X ray scattering (SAXS) collection of illustrative plates, has three qValue is than being the diffraction maximum of 1:2:3.

2. nano composite material as claimed in claim 1 is characterized in that: said As-made intermediate, it has the small angle X ray scattering curve shown in a among Fig. 1.

3. according to claim 1 or claim 2 nano composite material, it is characterized in that: the nitrogen adsorption/desorption isotherm of the mesoporous polymer/monox nanometer composite of said tool one dimension stratiform pore passage structure has the triangle hysteresis loop.

4. like the preparation method of the mesoporous polymer/monox nanometer composite of each said tool one dimension stratiform pore passage structure of claim 1～3; It is characterized in that: with bi-block copolymer dimethyl silicone polymer-polyoxyethylene (PDMS-PEO) and triblock polymer polyoxyethylene-poly-oxypropylene polyoxyethylene (PEO-PPO-PEO; P123) THF solution; Mix, dry reaction with the THF solution of phenolic resins performed polymer, make the mesoporous polymer/monox nanometer composite of tool one dimension stratiform pore passage structure again through roasting; Said drying time is 20～30h, and temperature is 80～100 ℃.

5. preparation method as claimed in claim 4 is characterized in that: said PDMS-PEO block copolymer, for M _w=3012, DMS ₃₂-EO ₂₀PDMS-PEO.

6. like claim 4 or 5 described preparation methods, it is characterized in that: said roasting is at 300 ~ 400 ℃ of roasting 2 ~ 4h with said As-made intermediate.

7. like claim 4,5 or 6 described preparation methods, it is characterized in that: the mass percentage concentration of the THF solution of said phenolic resins performed polymer is 15 ~ 40wt%; In the THF solution of PDMS-PEO and P123, the mass percentage concentration of PDMS-PEO and P123 is 2 ~ 5wt%.

8. like claim 4,5,6 or 7 described preparation methods, it is characterized in that: the mass ratio of said PDMS-PEO, P123 and Resol is (0.8 ~ 1.1): (0.8 ~ 1.1): (2.5 ~ 3.5).

9. method as claimed in claim 4, carry out as follows:

P123 and PDMS-PEO are dissolved among the THF, and 38 ~ 45 ℃ are stirred the solution that 8 ~ 15 min obtain homogeneous transparent, and the THF solution, stirring 0.3 ~ 0.7 h that add phenolic resins performed polymer Resol then obtain uniform solution; The mass ratio of above-mentioned substance is PDMS-PEO:P123:Resol=1:1:3; The mass percentage concentration of the THF solution of phenolic resins performed polymer is 20wt%, and in the THF solution of PDMS-PEO and P123, the mass percentage concentration of PDMS-PEO and P123 is 3.2wt%; Above-mentioned solution is transferred in the culture dish, and 5～8 h that volatilize under the room temperature place 24h in 100 ℃ of baking ovens with culture dish again, obtain transparent orange-yellow thin-film material; Above-mentioned material is scraped from culture dish, and grind into powder obtains the As-made sample;

Place tube furnace under the nitrogen gas protection, to carry out roasting in above-mentioned As-made sample, 300 ~ 400 ℃ of roasting 2 ~ 4h obtain the mesoporous polymer/monox nanometer composite of tool one dimension stratiform pore passage structure, and programming rate is 5 ℃/min.

10. method as claimed in claim 4, carry out as follows:

0.5 g P123 and 0.5 g PDMS-PEO are dissolved in the 30.0 g oxolanes (THF), and 40 ℃ are stirred 10 min, obtain the solution of transparent and homogeneous;

The THF solution that adds 7.5g 20 wt % phenolic resins performed polymers then stirs 0.5h and obtains uniform solution;

Above-mentioned solution is transferred in the culture dish, and 5～8 h that volatilize under the room temperature place 24h in 100 ℃ of baking ovens with culture dish again, obtain transparent orange-yellow thin-film material; Above-mentioned material is scraped from culture dish, and grind into powder obtains the As-made sample;

Place tube furnace under 350 ℃ of nitrogen gas protections, to carry out mesoporous polymer/monox nanometer composite that roasting 3h makes tool one dimension stratiform pore passage structure in the As-made sample, programming rate is 5 ℃/min.

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