阅读说明：本技术 一种复合催化减毒剂及其制备方法和应用 (Composite catalytic detoxifying agent and preparation method and application thereof ) 是由 袁尧 王伟 刘跃军 于 2021-09-14 设计创作，主要内容包括：本发明提供了一种复合催化减毒剂及其制备方法和应用,涉及材料技术领域。一种复合催化减毒剂的制备方法,以二氧化锰纳米片为支撑材料,通过层层自组装的方法将壳聚糖、海藻酸钠和镍离子沉积在二氧化锰纳米片表面。首先采用二氧化锰纳米片为支撑材料,提供了更大的比表面积和更多的活性中心,进而引入天然环保的生物质材料壳聚糖和海藻酸钠,并且利用了镍离子和海藻酸钠良好的络合能力,制备得到的复合催化减毒剂可以在低添加量的情况下表现出优异的阻燃性能和抑烟减毒性能。在硬质聚氨酯泡沫材料中引入复合催化减毒剂,使得硬质聚氨酯泡沫材料表现出优异的成炭性能和阻燃性能,并降低了材料在热解和燃烧过程中有毒烟气的释放。(The invention provides a composite catalytic toxicity reducing agent, a preparation method and application thereof, and relates to the technical field of materials. A preparation method of a composite catalytic toxicity reducing agent is characterized in that manganese dioxide nanosheets are used as supporting materials, and chitosan, sodium alginate and nickel ions are deposited on the surfaces of the manganese dioxide nanosheets by a layer-by-layer self-assembly method. Firstly, manganese dioxide nanosheets are used as supporting materials, larger specific surface area and more active centers are provided, natural and environment-friendly biomass materials chitosan and sodium alginate are introduced, good complexing capacity of nickel ions and sodium alginate is utilized, and the prepared composite catalytic attenuation agent can show excellent flame retardant performance and smoke suppression and attenuation performance under the condition of low addition amount. The composite catalytic attenuation agent is introduced into the rigid polyurethane foam material, so that the rigid polyurethane foam material has excellent char forming performance and flame retardant property, and the release of toxic smoke in the pyrolysis and combustion processes of the material is reduced.)

1. The preparation method of the composite catalytic toxicity reducing agent is characterized by taking manganese dioxide nanosheets as a supporting material and depositing chitosan, sodium alginate and nickel ions on the surfaces of the manganese dioxide nanosheets by a layer-by-layer self-assembly method.

2. The method for preparing the composite catalytic toxicity reducing agent according to claim 1, comprising:

s1: adjusting the pH value of the chitosan aqueous solution to 4.5-5, then adding the chitosan aqueous solution into the manganese dioxide suspension, and continuously stirring to obtain a first suspension.

S2: centrifuging, filtering and washing the first suspension, and dispersing the product into deionized water under the action of ultrasonic stirring to obtain a second suspension; adding an aqueous sodium alginate solution to the second suspension and stirring.

S3, centrifuging, filtering and washing the second suspension, and dispersing the product into deionized water under the action of ultrasonic stirring to obtain a third suspension; adding water-soluble nickel salt into the third suspension and stirring.

3. The method for preparing a composite catalytic toxicity reducing agent according to claim 2, further comprising, before S1, preparing the manganese dioxide suspension: dissolving potassium permanganate in deionized water, adding ethyl acetate, performing reflux reaction, cooling, centrifuging, washing and drying to obtain manganese dioxide; adding the manganese dioxide into deionized water and stirring.

4. The method for preparing a composite catalytic abatement agent according to claim 3, wherein the manganese dioxide has a crystal structure of δ -MnO₂The surface of the sheet is negatively charged.

5. The preparation method of the composite catalytic detoxification agent as claimed in claim 2, wherein the mass ratio of the chitosan to the sodium alginate is 1:1-1: 1.5.

6. The preparation method of the composite catalytic toxicity reducing agent according to claim 2 or 5, wherein the concentration of the water-soluble nickel salt is 30-40 mmol/L.

7. A composite catalytic abatement agent, prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the composite catalytic attenuation agent of claim 7 in the preparation of rigid polyurethane foam.

9. The use of a composite catalytic attenuation agent according to claim 8 in the preparation of rigid polyurethane foams, wherein the composite catalytic attenuation agent is added in an amount of 1-4 wt% based on the total mass.

10. The application of the composite catalytic attenuation agent in preparing rigid polyurethane foam materials according to claim 9, characterized by further comprising the addition of ammonium polyphosphate, wherein the addition amount of the ammonium polyphosphate is 10-30 wt% of the total mass.

Technical Field

The invention relates to the technical field of materials, and particularly relates to a composite catalytic toxicity reducing agent, and a preparation method and application thereof.

Background

The hard polyurethane foam (RPUF) material has excellent energy-saving and heat-insulating properties, compressive strength, chemical stability and adhesive property, so that the hard polyurethane foam (RPUF) material is widely applied to the fields of buildings, petroleum, transportation and the like and has a wide prospect. However, its structure is composed of repeating carbamate (-NH- (C ═ O) -O-) groups and the foam contains a large number of porous structures, which results in RPUF, upon ignition, generating a large amount of heat and gaseous products in a short period of time, including noxious smoke particles and carbon monoxide (CO), Nitrogen Oxides (NO), among others_x) And toxic gases such as Hydrogen Cyanide (HCN) increase the incidence of fire and the fatality of fire, posing a significant threat to personnel and property safety. Therefore, the reduction of the fire risk of rigid polyurethane foams is imminent.

According to the literature reports, some transition metal (Ni, Mo, Co, Cu and the like) materials are used as catalysts or carriers for the purpose of reducing and removing nitrogen oxides in the forms of metal nanoparticles, oxides, carbides and the like. In addition, these nanometal materials can be used to eliminate volatile organic compounds and reduce the release of toxic gases.

In recent years, manganese dioxide, a promising green nanomaterial, attracts attention due to its high natural abundance, low cost, simple preparation method, good environmental compatibility, structural diversity, and unique physical and chemical properties. MnO hitherto₂Has been widely applied to the fields of lithium ion batteries, gas sensors, catalysis and the like. By controlling experimental conditions and synthesis method, MnO₂The nanomaterial can be made into various geometric forms such as a rod, a sheet, a flower, a strip and a tree, and exhibits different excellent properties. Thus, MnO was modified₂And has important significance in expanding the application of the method to other fields. However, the biomass materials such as chitosan, sodium alginate and the like are deposited in MnO by a layer-by-layer self-assembly method₂The research on the surface and the smoke suppression and toxicity reduction performance thereof is not reported so far.

Disclosure of Invention

The invention aims to provide a preparation method of a composite catalytic toxicity reducing agent, which is simple and feasible and can prepare the toxicity reducing agent with stable structure and good dispersibility.

The second purpose of the invention is to provide a composite catalytic toxicity reducing agent which has a stable structure and good dispersibility, and after the toxicity reducing agent is introduced into rigid polyurethane foam, toxic smoke generated by combustion of the rigid polyurethane foam can be reduced, so that the composite catalytic toxicity reducing agent is very environment-friendly.

The third purpose of the invention is to provide an application of the composite catalytic detoxifying agent in the rigid polyurethane foam material, and the rigid polyurethane foam material has excellent char forming performance and flame retardant performance and low toxic smoke release in the pyrolysis and combustion processes by applying the composite catalytic detoxifying agent in the rigid polyurethane foam material.

The invention is realized by the following steps:

a preparation method of a composite catalytic toxicity reducing agent comprises the steps of taking manganese dioxide nanosheets as a supporting material, and depositing chitosan, sodium alginate and nickel ions on the surfaces of the manganese dioxide nanosheets by a layer-by-layer self-assembly method.

A composite catalytic toxicity-reducing agent is prepared by the preparation method.

The application of the composite catalytic toxicity reducing agent in rigid polyurethane foam materials.

The composite catalytic toxicity reducing agent, the preparation method thereof and the application thereof in the hard polyurethane foam material have the beneficial effects that:

a preparation method of a composite catalytic toxicity reducing agent is characterized in that manganese dioxide nanosheets are used as supporting materials, and chitosan, sodium alginate and nickel ions are deposited on the surfaces of the manganese dioxide nanosheets by a layer-by-layer self-assembly method. According to the invention, manganese dioxide nanosheets are used as supporting materials, larger specific surface area and more active centers are provided, natural and environment-friendly biomass materials of chitosan and sodium alginate are adopted, and good complexing capability of nickel ions and sodium alginate is utilized, so that the prepared toxicity reducing agent has good compatibility with a polymer matrix, and can show excellent flame retardant performance and smoke suppression toxicity reducing performance under the condition of low addition; fully exerts the advantages of the promotion of carbon formation and flame retardance of the chitosan and the sodium alginate and the catalytic attenuation of the nickel-containing quantum dot/manganese dioxide nano-sheet layer.

The composite catalytic toxicity reducing agent is applied to rigid polyurethane foam materials. The composite catalytic attenuation agent is introduced into the rigid polyurethane foam material, so that the rigid polyurethane foam material has excellent char forming performance and flame retardant property, and the release of toxic smoke in the pyrolysis and combustion processes of the material is reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is an X-ray diffraction curve of manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent prepared in example 1 of the present invention;

FIG. 2 is a Fourier transform infrared spectrum of a manganese dioxide and manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic abatement agent prepared in example 1 of the present invention;

FIG. 3 is a transmission electron micrograph of manganese dioxide prepared according to example 1 of the present invention.

FIG. 4 is a transmission electron microscope image of the manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent prepared in example 1 of the present invention.

FIG. 5 is a high resolution TEM image of the manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent prepared in example 1 of the present invention.

FIG. 6 shows the EDX spectrum of manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifier prepared in example 1 of the present invention.

Fig. 7 is a flow chart of a preparation method of the manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent prepared in example 2 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The invention provides a preparation method of a composite catalytic toxicity reducing agent, which comprises the steps of taking manganese dioxide nano-sheets as a supporting material, and depositing chitosan, sodium alginate and nickel ions on the surfaces of the manganese dioxide nano-sheets by a layer-by-layer self-assembly method.

According to the invention, the manganese dioxide nanosheet is used as a supporting material, so that a larger specific surface area and more active centers are provided, natural and environment-friendly biomass materials chitosan and sodium alginate are introduced, and good complexing capability of nickel ions and sodium alginate is utilized, so that the prepared nickel quantum dot/manganese dioxide nanosheet layer has good compatibility with a polymer matrix, and can show excellent flame retardant performance and smoke suppression and toxicity reduction performance under the condition of low addition; fully exerts the advantages of the promotion of carbon formation and flame retardance of the chitosan and the sodium alginate and the catalytic attenuation of the nickel-containing quantum dot/manganese dioxide nano-sheet layer.

Preferably, comprising S1: adjusting the pH value of the chitosan aqueous solution to 4.5-5, then adding the chitosan aqueous solution into the manganese dioxide suspension, and continuously stirring; a first suspension is obtained.

S2: centrifuging, filtering and washing the first suspension, and dispersing the product into deionized water under the action of ultrasonic stirring to obtain a second suspension; adding the sodium alginate aqueous solution into the second suspension, and stirring.

S3, centrifuging, filtering and washing the second suspension, and dispersing the product into deionized water under the action of ultrasonic stirring to obtain a third suspension; adding the water-soluble nickel salt into the third suspension and stirring.

Preferably, in S1, the acid used for adjusting the pH of the solution is one of dilute hydrochloric acid and dilute sulfuric acid.

Preferably, in S3, the water-soluble nickel salt is one of chloride, sulfate, bromide and nitrate.

Preferably, prior to S1, further comprising the preparation of a manganese dioxide suspension: dissolving potassium permanganate in deionized water, adding ethyl acetate, performing reflux reaction, cooling, centrifuging, washing and drying to obtain manganese dioxide; adding manganese dioxide into deionized water and stirring. The method can be used for preparing manganese dioxide suspension with more stable property.

Preferably, the manganese dioxide has a crystal structure of delta-MnO₂The surface of the sheet is negatively charged. The manganese dioxide with the structure can ensure that chitosan, sodium alginate and nickel ions are deposited on the surface of the manganese dioxide more stably.

Preferably, the mass ratio of the chitosan to the sodium alginate is 1:1-1: 1.5.

Preferably, the concentration of the water-soluble nickel salt is 30-40 mmol/L.

A composite catalytic detoxifying agent is prepared by the preparation method of the composite catalytic detoxifying agent.

The composite catalytic toxicity reducing agent is applied to rigid polyurethane foam materials. The composite catalytic attenuation agent is introduced into the hard polyurethane foam material, so that the hard polyurethane foam material has excellent char forming performance and flame retardant property, and the release of toxic smoke in the pyrolysis and combustion processes of the material is reduced.

Preferably, the amount of the composite catalytic attenuation agent added is 1-4 wt% of the total mass.

Preferably, the method also comprises the step of adding ammonium polyphosphate, wherein the adding amount of the ammonium polyphosphate is 10-30 wt% of the total mass. The composite catalytic toxicity reducing agent and the ammonium polyphosphate are used together to improve the thermal stability and the flame retardant property of the hard polyurethane foam and reduce the release of toxic smoke in the combustion process.

The following description will be given with reference to specific examples.

Example 1

Firstly, preparing a manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent:

in the first step, 2.37g of potassium permanganate and 750ml of deionized water are placed in a three-neck flask, and after the potassium permanganate is completely dissolved, 200ml of ethyl acetate is added and the mixture is refluxed at 95 ℃ overnight. The brown product is washed by multiple filtrations and dried under vacuum at 80 c overnight and milled to give brown powdered manganese dioxide.

In the second step, 1g of manganese dioxide powder is placed in 500ml of deionized water and mechanically stirred for 2 h. 100mL of a 0.2% strength by weight chitosan solution are prepared, the pH is adjusted to 5 with dilute hydrochloric acid and added to the suspension. After stirring for 2h, the suspension was centrifuged and washed with water.

And thirdly, dispersing the product into 500ml of water under the action of stirring and ultrasonic waves. 100mL of a 0.3 wt% sodium alginate solution was added to the suspension. After stirring for 2h, the suspension was centrifuged and washed with water.

And fourthly, dispersing the product in 500ml of water, dropwise adding 10ml of nickel chloride aqueous solution with the concentration of 30mmol/L, mechanically stirring for 2 hours, centrifuging the suspension, washing with water, and drying overnight to obtain the manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent.

The X-ray diffraction curve, fourier transform infrared spectrum and EDX spectrum of the manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent prepared in example 1 are shown in fig. 1, fig. 2 and fig. 6, which illustrate the successful preparation of the composite material. As can be seen from the transmission electron microscope images of the manganese dioxide and manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent shown in fig. 3, 4 and 5, nickel particles with a particle size of about 2nm are uniformly distributed on the surface of the manganese dioxide nanosheet, and no large lamellar is aggregated and stacked.

Preparation and testing of rigid polyurethane foams

In the embodiment, the formula of the rigid polyurethane foam according to parts by mass is as follows:

according to the formula, 3 parts of manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent and 15 parts of ammonium polyphosphate are added into a white material (mixture of other components) of rigid polyurethane foam, fully stirred for 10 seconds by a high-speed mechanical stirrer, and then the obtained product is injected into a mold (the size is 250 x 150 x 60 mm)³) And after foam is initiated, putting the mixture into an oven at 70 ℃ for curing for 48 hours to complete the polymerization reaction, thus obtaining the flame-retardant rigid polyurethane foam composite material. The UL-94 vertical burning test can pass the V-0 test.

Example 2

Firstly, preparing manganese dioxide @ chitosan @ sodium alginate @ nickel nano composite catalytic detoxifying agent (refer to the preparation schematic diagram of fig. 7):

step one, preparing 12ml of 1mol/L tetramethylammonium hydroxide solution, 12ml of 30 wt% hydrogen peroxide solution and 16ml of deionized water into a mixed solution, adding the mixed solution into 20ml of 0.3mol/L manganese chloride aqueous solution within 15s, continuously mechanically stirring for 8h, filtering and washing the obtained dark brown suspension with deionized water, and drying in vacuum to obtain manganese dioxide nanosheets.

In the second step, 1g of manganese dioxide powder is placed in 500ml of deionized water and mechanically stirred for 2 h. 100mL of a 0.3 wt% sodium alginate solution was prepared and added to the suspension. After stirring for 2h, the suspension was centrifuged and washed with water.

In the third step, the product is placed in 500ml of deionized water and mechanically stirred for 2 hours. 100mL of a 0.2% strength by weight chitosan solution are prepared, the pH is adjusted to 5 with dilute hydrochloric acid and added to the suspension. After stirring for 2h, the suspension was centrifuged and washed with water.

In the fourth step, the product is placed in 500ml of deionized water and mechanically stirred for 2 h. 100mL of a 0.3 wt% sodium alginate solution was prepared and added to the suspension. After stirring for 2h, the suspension was centrifuged and washed with water.

And fifthly, dispersing the product in 500ml of water, dropwise adding 10ml of nickel chloride aqueous solution with the concentration of 30mmol/L, mechanically stirring for 2 hours, centrifuging the suspension, washing with water, and drying overnight to obtain the manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent.

Preparation and testing of rigid polyurethane foams

In the embodiment, the formula of the rigid polyurethane foam according to parts by mass is as follows:

according to the formula, 3 parts of manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic detoxifying agent and 20 parts of ammonium polyphosphate are added into a white material of hard polyurethane foam, fully stirred for 10 seconds by a high-speed mechanical stirrer, and then the obtained product is injected into a mold (the size is 250 multiplied by 150 multiplied by 60 mm)³) And after foam is initiated, putting the mixture into an oven at 70 ℃ for curing for 48 hours to complete the polymerization reaction, thus obtaining the flame-retardant rigid polyurethane foam composite material. The fire safety performance of the composite material is represented by a cone calorimeter, and compared with pure hard polyurethane foam, the thermal release rate peak value of the hard polyurethane foam composite material can be reduced by 30% by adding 3 wt% of manganese dioxide @ chitosan @ sodium alginate @ nickel composite catalytic toxicity reducing agent, and the hard polyurethane foam composite material has a strong catalytic carbonization effect. Therefore, the manganese dioxide sheet layer modified by the layer-by-layer self-assembly technology has high-efficiency flame retardant performance and char formation performance.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.