CN1260281C - Method of preparing modified imvite for polymer/inorganic nano composite material - Google Patents

Abstract

The present invention relates to an easy and practical preparation method of a modified montmorillonite clay for a polymer /inorganic nano composite material. In the method, montmorillonite clay and an organic modifier or a mixed organic modifier directly bear modification reaction under the solid powdered condition; the obtained modified montmorillonite clay can be directly used for a polymer /montmorillonite clay nano composite material; the effective intercalation of polymer macromolecules among layers of montmorillonite clay is realized, and the nano composite material with favorable performance is obtained. The method has the advantages of simple and practical design, low production cost, no use of water or solvents, no environmental pollution, etc. and has a favorable industrial application prospect.

Description

Preparation method of modified montmorillonite for polymer/inorganic nanocomposite

technical field

The invention relates to the field of polymer/inorganic nanocomposite materials, in particular to a preparation method of modified montmorillonite for polymer/inorganic nanocomposite materials.

Background technique

Nanocomposites (Nanocomposites) refer to composite materials whose dispersed phase scale is less than 100 nm in at least one dimension. Due to the small size and large specific surface area of the nanophase, the number of surface atoms, surface tension and surface energy increase sharply with the decrease of particle size, thus having significant small size effect, quantum size effect, surface effect and macroscopic quantum tunneling effect, etc. , endowing materials with many novel properties and rules, and showing broad prospects for the research and application of nanocomposites.

Nanocomposite materials composed of polymers and inorganic substances are the most active nanocomposite materials in recent years. The combined use of polymers and inorganic substances has a history of decades, and inorganic minerals such as clay, calcium carbonate, and mica have been widely used as fillers for polymers. The development of nanocomposite concepts and technologies has endowed this kind of organic-inorganic composite materials with new vitality, which not only makes it possible to significantly improve the comprehensive properties of such materials, but also enables composite materials to have many unexpected new physical and chemical properties. It has shown broad development prospects in the application field of new materials.

There are many preparation methods for polymer/inorganic nanocomposites, among which the intercalation composite method or intercalation composite method is the most researched at home and abroad, and has the most use value and development prospect. This method is to use some inorganic materials (such as montmorillonite, kaolin, modified graphite, etc.) to have the characteristics of nano-sheet structure, and to insert monomers into the interlayer on the basis of organic modification of the interlayer surface. And carry out in-situ polymerization reaction, or macromolecules are directly intercalated between the layers in the state of solution, melt, or emulsion, and finally obtain exfoliated nanocomposites (Exifoliated nanocomposites) with completely separated nanosheets or intercalation with nanometer-sized interlayers Nanocomposites (Intercalated nanocomposites).

Montmorillonite is a natural layered silicate inorganic material with a nanosheet structure. Because of its unique structure, easy source and low price, it is especially used in the preparation and application of polymer/inorganic nanocomposites. received people's attention. The composite of polymer and montmorillonite at the nanoscale makes the material have the characteristics of light specific gravity, good heat resistance, high barrier property, good aging resistance and excellent flame retardancy.

The main component of montmorillonite is montmorillonite. Montmorillonite belongs to the 2:1 type layered silicate, that is, each unit cell is composed of two layers of silicon-oxygen tetrahedron sandwiched by a layer of aluminum-oxygen octahedron, and the two are connected by shared oxygen atoms. The thickness of the layer is about 1nm, and the length and width are about 100nm. Since part of the aluminum atoms on the aluminum oxygen octahedron are replaced by low-valent atoms (such as Mg ²⁺ , Fe ²⁺ , Na ^+, etc.), the inner surface of the layer has negative charges, and the excess negative charges are due to the free Mg ²⁺ , Fe ²⁺ , Na ⁺ and other cations balance. Due to the hydrophilicity of the surface of montmorillonite, it is unfavorable for its dispersion in polymers, wetting and intercalation by polymers. In order to overcome this shortcoming, it must be modified in advance to make the interlayer surface of montmorillonite hydrophobic. Effective organic modification of montmorillonite is the key to the successful preparation of polymer/montmorillonite nanocomposites.

Montmorillonite is easy to carry out ion exchange reaction with alkyl quaternary ammonium salt, pyridine derivatives or other organic cations to generate organic modified silicate. The organically modified silicate is lipophilic, and the interlayer spacing increases, which can effectively intercalate with monomers or polymers, and evenly disperse in the polymer matrix at the nanometer scale, thereby forming nanocomposites.

The currently commonly used quaternary ammonium salt modified montmorillonite process is usually carried out in aqueous suspension or organic solvent, and the process is relatively complicated. It needs to be dispersed and pulped, ion exchange reaction, aging, filtering, washing, drying, grinding, and screening. A series of processes, such as raw materials and energy consumption, lead to a sharp increase in the cost of organically modified montmorillonite, and at the same time cause environmental pollution, thus affecting the popularization and application of intercalation nanocomposite technology.

Contents of the invention

The purpose of the present invention is to aim at the existing polymer/montmorillonite nano-intercalation composite technology, which needs complicated organic modification of montmorillonite, water or organic solvent should be used in the preparation process, the cost is high, and it is not conducive to popularization Shortcomings such as using etc., provide a kind of simple and feasible preparation method of modified montmorillonite for polymer/inorganic nanocomposite materials, montmorillonite and a kind of organic modifier or mixed organic modifier in solid powder state Direct reaction modification, the obtained modified montmorillonite can be directly used in polymer/montmorillonite nanocomposites to realize effective intercalation of polymer macromolecules between montmorillonite layers and obtain nanocomposites with excellent properties . The method has the advantages of simplicity, low production cost, no need to use water or solvent, no environmental pollution, etc., and has good industrial application prospects.

The preparation method of modified montmorillonite for polymer/inorganic nanocomposite of the present invention comprises the steps:

(1) Mix and stir 100 parts by weight of powdered montmorillonite and 1 to 50 parts by weight of an organic modifier at room temperature to 150°C;

(2) heating the mixture obtained in (1) to 50-150° C. for solid phase stirring reaction for 10-100 min;

(3) cooling the product obtained in (2) to normal temperature promptly obtains the modified montmorillonite for the polymer/inorganic nanocomposite;

The preferred solution of the present invention:

(1) Mix and stir 100 parts by weight of powdered montmorillonite and 10 to 30 parts by weight of an organic modifier at 50 to 120° C.;

(2) heating the mixture obtained in (1) to 80-120° C. for solid phase stirring reaction for 30-80 minutes;

(3) cooling the product obtained in (2) to normal temperature to obtain the modified montmorillonite for polymer/inorganic nanocomposite materials.

The montmorillonite includes one or more mixtures of calcium-based or sodium-based montmorillonites of various specifications;

The organic modifier includes one or more mixtures of various organic amines or organic quaternary ammonium salts. Organic quaternary ammonium salts such as cetyltrimethylammonium chloride or cetyltrimethylammonium bromide, octadecyltrimethylammonium chloride or octadecyltrimethylammonium bromide, formazan Dimethylaminoethyl Acrylate Trimethylammonium Chloride, p-(vinylbenzene)trimethylammonium Chloride, Hexadecyl Dimethallyl Ammonium Chloride, p-(vinylbenzyl)dodecyl One or more of alkyl dimethyl ammonium chloride or p-(vinylbenzyl) cetyl dimethyl ammonium chloride;

Organic amines are aniline, dodecylamine, octadecylamine, caprolactam or 6-aminocaproic acid, etc.;

The silane coupling agent is γ-(2,3 glycidoxy)propyltrimethylsilane, methylvinylsilane, N,N'-bis(2-methyl-2-nitropropyl) -1,6-diaminohexane, bis(3-triethoxysilylpropyl)tetrasulfide, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(β-methoxy Ethoxy)silane, methacryloxypropyltrimethoxysilane or ethylenediaminomethyltriethoxysilane;

Titanate coupling agents are isopropoxy triisostearate titanium, isopropoxy tri(dioctyl phosphate) titanium, isopropoxy tri(dioctyl pyrophosphate) titanium, bis(dioctyl phosphate) Octyl) ethylene glycol titanate or di(dioctyl pyrophosphate) titanium glycolate, etc.

The present invention adds a modifier or a mixed modifier to the montmorillonite, and performs the modification of the montmorillonite under solid phase conditions, which saves the complicated steps of the organic modification of the montmorillonite currently in general use, and saves costs. while being convenient to use. On the one hand, the modifier enters the interlayer of montmorillonite and combines with montmorillonite through physical and chemical effects during solid-state reaction; And/or chemical action combined with polymer molecular chains, so that the polymer macromolecular chains are embedded between the modified montmorillonite layers, the distance between the montmorillonite layers is expanded, and even the sheets are peeled off, so that the nanometer size of the polymer and montmorillonite is realized. Composite, thus significantly improving the properties of polymer/montmorillonite nanocomposites. For example, the tensile strength, elongation at break, and tear strength of general vulcanized rubber of natural rubber and 5 parts of unmodified montmorillonite are 16.6Mpa, 620% and 20.8kN/m respectively, while 5 parts of montmorillonite The tensile strength, elongation at break, and tear strength of the nanocomposite vulcanizate prepared with natural rubber after solid phase modification were 24.4Mpa, 546%, and 36.8kN/m, respectively, reaching 30 parts of high resistance Reinforcement level of furnace black (N330). These results show that the solid-state method modified montmorillonite is used in the preparation of polymer nanocomposites, and good results have been obtained.

The modified montmorillonite prepared by the invention can be applied to various polymer materials such as plastics, rubber, fibers, adhesives, coatings and composite materials thereof, and has broad application prospects.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The method for organic modification of montmorillonite by solid-phase method in the present invention is technically simple and easy, saves the complicated steps of organic modification of montmorillonite by existing water-phase method, and has simple process, low production cost, It has the advantages of no solvent recovery problem, no environmental pollution, etc., and has a good industrial application prospect.

2. The modified montmorillonite prepared by the method of the present invention can be used to prepare various high-performance polymer/montmorillonite nanocomposites.

Detailed ways

Example 1

(1) Get 100 grams of montmorillonite at room temperature, add 1 gram of cetyltrimethylammonium chloride, and stir well;

(2) The above mixture was stirred and reacted at 150° C. for 10 minutes;

(3) above-mentioned reaction product is cooled to room temperature and promptly obtains modified montmorillonite of the present invention;

Take 100 grams of natural rubber, add various compounding agents and the above-mentioned modified montmorillonite according to the commonly used rubber formula, carry out mixing and vulcanization, and the properties of the obtained vulcanized rubber are shown in Table 1. It can be seen from Table 1 that the performance of natural rubber/modified montmorillonite nanocomposites is significantly better than that of natural rubber and unmodified montmorillonite composites, adding 1-10 parts of modified montmorillonite can show significant Reinforcing effect and improved aging resistance.

Table 1 Physical and mechanical properties of natural rubber/modified montmorillonite nanocomposites natural rubber Natural rubber/montmorillonite (10phr) Natural Rubber/Modified Montmorillonite Montmorillonite dosage 1 10 20 100% modulus stress/Mpa 0.81 0.75 0.83 1.21 1.16 300% modulus stress/Mpa 1.83 1.84 2.71 4.23 4.20 500% modulus stress/Mpa 5.61 5.35 5.49 11.83 10.56 Tensile strength/Mpa 20.53 14.74 19.64 27.17 25.68 Elongation at break/% 765 700 715 713 705 Tear strength/KN/m 20.6 21.12 22.77 40.30 30.56 Permanent deformation at break/% 18 17 twenty three 25 26 Hardness (Shore A)/degree 42 43 45 49 51 Performance decline rate after aging/% (100℃×48h in air) 46.2 38.2 29.3 26.8 33.6

Note: (1) Mixed rubber formula: NR100, stearic acid 2, zinc oxide 4, accelerator CZ 1.0, accelerator DM 0.5, antioxidant 4010NA 1.0, sulfur 1.5. The vulcanization condition is 143°C×T90.

(2) The decline rate of performance after aging is the decline rate of the product of tensile strength and elongation at break.

Figure 1 is the TEM photograph of the natural rubber/modified montmorillonite nanocomposite material when the amount of modified montmorillonite is 10 parts. It can be seen from the figure that the modified montmorillonite is dispersed in the material to the nanometer level, and the The size of part of the montmorillonite dispersed phase is within 10nm. From the XRD pattern in Figure 2, it can be seen that the layer spacing of montmorillonite in this material has expanded from the original 1.6nm to 4.3nm, indicating that the modified montmorillonite prepared by this method has successfully produced rubber/montmorillonite nanocomposites.

Example 2

(1) Take 100 grams of montmorillonite and heat it to 50°C, add 50 grams of γ-(2,3 glycidoxy)propyltrimethylsilane, and stir well;

(2) Stir and react the above mixture at 50°C for 30min;

(3) above-mentioned reaction product is cooled to room temperature and promptly obtains modified montmorillonite of the present invention;

Take 100 grams of butadiene rubber, add 5 grams of modified montmorillonite, and add various compounding agents according to the commonly used rubber formula, carry out mixing and vulcanization, and the properties of the obtained vulcanized rubber are shown in Table 2. It can be seen from Table 2 that the performance of butadiene rubber/modified montmorillonite nanocomposites is significantly better than that of butadiene rubber/montmorillonite composites, and 5 parts of modified montmorillonite can show a similar performance to 20 parts of carbon black. Significant reinforcing effect.

Table 2 Physical and mechanical properties of butadiene rubber/montmorillonite nanocomposites by mechanical blending in situ intercalation Butadiene rubber Butadiene Rubber/Montmorillonite (5 parts) Butadiene rubber/modified montmorillonite (5 parts) Butadiene Rubber/Carbon Black (N330, 20 parts) 300% tensile stress (Mpa) breaking strength/Mpa breaking elongation/% breaking permanent deformation/% tearing strength/KN/m hardness (Shore A)/degree 1.381.53320611.5639 1.181.49305612.8141 4.565.68501626.1946 3.136.46383628.7849

Note: The compounding formula is as follows: butadiene rubber 100, stearic acid 2, zinc oxide 4, accelerator CZ1.0, accelerator DM0.5, anti-aging agent 4010NA1.0, sulfur 1.5. The vulcanization condition is 151°C×T90.

Figure 3 is a TEM photo of the butadiene rubber/modified montmorillonite nanocomposite when the amount of modified montmorillonite is 5 parts. It can be seen from the figure that the modified montmorillonite is dispersed in the material to reach the nanometer level. The size of most dispersed phases of montmorillonite is within 20nm. From the XRD pattern of Figure 4, it can be seen that the layer spacing of montmorillonite in this material has expanded from the original 1.3nm to 4.2nm, indicating that the modified montmorillonite prepared by this method has successfully produced rubber/montmorillonite nanocomposites.

Example 3

(1) Take 100 grams of montmorillonite and heat it to 80°C, add caprolactam and 15 grams each of isopropoxytitanium triisostearate, and stir well;

(2) Fully stir the above mixture at 100°C for 100 minutes;

(3) cooling the above reaction product to room temperature to obtain organically modified montmorillonite.

Take 100 grams of styrene-butadiene rubber, add 30 grams of modified montmorillonite, and add various compounding agents according to the commonly used rubber formula for mixing and vulcanization. Carry out X-ray diffraction analysis to the obtained vulcanizate, find that the interlayer spacing of montmorillonite in this material expands to 4.7nm from original 1.5nm, illustrate that the modified montmorillonite prepared by this method has successfully produced rubber/ Montmorillonite nanocomposites.

Example 4

(1) Take 100 grams of montmorillonite and heat it to 120 ° C, add vinyl triethoxysilane, (p-vinylbenzyl) dodecyl dimethyl ammonium chloride 5 grams each

(2) Fully stir the above mixture at 120°C for 80 minutes;

(3) cooling the above reaction product to room temperature to obtain organically modified montmorillonite.

Take 100 grams of nitrile rubber, add 5 grams of modified montmorillonite, and add various compounding agents according to the commonly used rubber formula, and carry out mixing and vulcanization. Carry out X-ray diffraction test to the obtained vulcanizate, find that the interlayer spacing of montmorillonite in this material expands to 4.2nm from original 1.6nm, illustrate that the modified montmorillonite prepared by this method has successfully produced rubber/ Montmorillonite nanocomposites.

Claims (5)

1, a kind of preparation method of modified montmorillonite for polymer/inorganic nanocomposite material, it is characterized in that comprising the steps: (1) Mix and stir 100 parts by weight of powdered montmorillonite and 1 to 50 parts by weight of an organic modifier at room temperature to 150°C; (2) heating the mixture obtained in (1) to 50-150° C. for solid phase stirring reaction for 10-100 min; (3) cooling the product obtained in (2) to normal temperature promptly obtains the modified montmorillonite for the polymer/inorganic nanocomposite; The montmorillonite includes one or more mixtures of calcium-based or sodium-based montmorillonites of various specifications; organic modifiers include silane coupling agents, titanate coupling agents, various organic amines One or more mixtures of class or organic quaternary ammonium salts. 2. The preparation method of modified montmorillonite for polymer/inorganic nanocomposite according to claim 1, characterized in that it comprises the following steps: (1) Mix and stir 100 parts by weight of powdered montmorillonite and 10 to 30 parts by weight of an organic modifier at 50 to 120° C.; (2) heating the mixture obtained in (1) to 80-120° C. for solid phase stirring reaction for 30-80 minutes; (3) cooling the product obtained in (2) to normal temperature to obtain the modified montmorillonite for polymer/inorganic nanocomposite materials. 3. The preparation method of modified montmorillonite for polymer/inorganic nanocomposites according to claim 1 or 2, characterized in that the organic quaternary ammonium salt comprises cetyl trimethyl ammonium chloride or cetyl trimethyl ammonium chloride Alkyltrimethylammonium bromide, octadecyltrimethylammonium chloride or octadecyltrimethylammonium bromide, dimethylaminoethyl methacrylate trimethylammonium chloride, p-(vinyl Benzyl)trimethylammonium chloride, cetyldimethylallylammonium chloride, p-(vinylbenzyl)dodecyldimethylammonium chloride or p-(vinylbenzyl)cetyl One or more of alkyl dimethyl ammonium chloride. 4. The preparation method of modified montmorillonite for polymer/inorganic nanocomposites according to claim 1 or 2, characterized in that the organic amines are aniline, dodecylamine, octadecylamine, caprolactam or 6- Aminocaproic acid; the silane coupling agent is γ-(2,3 glycidoxy) propyltrimethylsilane, methylvinylsilane, N,N'-bis(2-methyl-2-nitro propyl)-1,6-diaminohexane, bis(3-triethoxysilylpropyl)tetrasulfide, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri( β-methoxyethoxy)silane, methacryloxypropyltrimethoxysilane or ethylenediaminemethyltriethoxysilane; titanate coupling agent is isopropoxy triisostearyl titanium isopropoxide, isopropoxytri(dioctyl phosphate)titanium, isopropoxytri(dioctyl pyrophosphate)titanium, bis(dioctyl phosphate)ethylene glycol titanate or bis(dioctyl pyrophosphate) Esters) titanium glycolate. 5. The modified montmorillonite for polymer/inorganic nanocomposite prepared by the method of claim 1.

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