Method for preparing rubber aerogel from waste tire rubber powder and application

Abstract

The invention discloses a method for preparing rubber aerogel by utilizing rubber powder generated by recycling waste tires, which comprises the following steps of: putting the rubber powder which is prepared in a laboratory and has good dispersity into a beaker containing deionized water, uniformly stirring, and then adding a binder solution to uniformly mix; and adding a dispersing agent to further improve the dispersity of the rubber powder in the solution, sequentially dropwise adding a catalyst and a cross-linking agent solution, uniformly stirring to obtain hydrogel, and freeze-drying by using a freeze-drying machine to obtain the rubber aerogel. The novel rubber aerogel is developed by adopting a freeze-drying technology and taking rubber powder recycled from waste tires as a raw material, and the prepared aerogel is expected to be applied to the fields of heat insulation and hydrophobic oil absorption through a certain technical means.

Description

Technical Field

[0001] The invention belongs to the technical field of green recycling of waste tire rubber powder, and in particular relates to aerogel preparation technology using rubber powder generated during waste tire recycling and its applications in heat insulation, hydrophobicity and oleophilicity. Background Art

[0002] The pollution of waste tires to the environment and their effective recycling and treatment are issues that must be addressed. The main component of waste tires is rubber, which is an important resource related to the country's economic development. Fully recycling waste tires and turning them into high value-added products can not only improve the problem of rubber shortage in my country, but also help enterprises embark on a green, ecological, low-carbon, energy-saving, environmentally friendly and efficient development route.

[0003] When the substances in the solution undergo physical and chemical crosslinking, a gel with a three-dimensional network structure is formed. After the gel is dried, Aerogels are those in which the liquid in the internal network structure of the gel is replaced by gas, the shape remains basically unchanged, and they have ultra-light properties, high porosity and specific surface area. The raw materials for preparing aerogels are also diversified, such as Al(OH)3 aerogel, SiO2 aerogel, cellulose aerogel, etc.

[0004] Regarding the use of waste materials to prepare aerogels, currently sugarcane bagasse, cotton, coffee grounds, coal lime, waste fibers, etc. have been used to prepare aerogels. However, there are few reports on the preparation of aerogels from waste rubber powder generated during the recycling of waste tires. If the waste rubber powder is prepared into aerogels and applied to the fields of thermal insulation or oil absorption, resource recycling can be maximized, which will provide a new development route for waste tire recycling.

[0005] The rubber aerogel in this application is aimed at the green recycling of waste tire rubber powder. It is not only cheaper (because the main component of waste tires is rubber), but also the prepared aerogel is functionally modified to have hydrophobic and heat-insulating properties, thus providing a new technical route for the green recycling of rubber in waste tires. Summary of the invention

[0006] The purpose of the present invention is to provide a technology for preparing rubber aerogel using waste rubber powder generated when recycling waste tires as raw materials and its application in the fields of heat insulation, hydrophobicity and lipophilicity. The method has easy-to-obtain raw materials, low production cost, can be industrialized, and has a wide range of applications.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a technical route for preparing rubber aerogel from dispersible rubber powder prepared in a laboratory, and the steps are as follows:

[0009] Add a binder, a dispersant, a cross-linking agent, a dispersible rubber powder and a catalyst into water in sequence at 20-80° C. and stir for 2-8 hours, then carry out a cross-linking reaction to obtain a hydrogel; then put the hydrogel into a refrigerator or a liquid nitrogen environment for freezing; put the frozen hydrogel into a vacuum freeze dryer to obtain a rubber aerogel.

[0010] In the above-mentioned method for preparing rubber aerogel, the mass ratio of the binder, dispersant, crosslinking agent, dispersible rubber powder and catalyst is preferably (0.4-0.8):(0.04-0.4):(1-8):(1-10):(2-8).

[0011] Preferably, the binder is a mixture of one or more of epoxy resin matrix, polyvinyl alcohol, polyethylene glycol, polyacrylamide, phenolic resin, silicone emulsion, styrene acrylic emulsion, hyaluronic acid, silk fibroin, chitosan, konjac glucomannan, and carboxymethyl cellulose.

[0012] Preferably, the dispersant is a mixture of one or more of starch, xanthan gum, gelatin, agar, carrageenan, guar gum, pectin, dextrin and sodium alginate.

[0013] Preferably, the cross-linking agent is a mixture of one or more of glyoxal, glutaraldehyde, boric acid, citric acid, genipin, sodium tetraborate oxalate.

[0014] Preferably, the dispersible rubber powder is a mixture of one or more of natural rubber, styrene-butadiene rubber, butadiene rubber or isoprene rubber with a mesh size of 40-200, and may be accompanied by some residual nylon fibers (a very small amount, accounting for about 10% of the total mass). -3 ).

[0015] Preferably, the catalyst is one or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, sodium hydroxide, potassium hydroxide, and ammonia water.

[0016] Preferably, the cross-linking reaction temperature is 40-90° C. and the time is 2-12 hours.

[0017] Preferably, the freeze-drying cold trap temperature is -50 to -80°C, and the time is 12-96h.

[0018] The present invention further provides a rubber aerogel prepared by the above method, wherein the dispersible rubber powder is physically entangled with a binder, a crosslinking agent and a dispersant to form a three-dimensional network structure through chemical crosslinking.

[0019] The present invention further provides the use of the rubber aerogel prepared by the method, which is used in the fields of heat insulation, oil absorption, etc.

[0020] In summary, the present invention has the following beneficial effects.

[0021] The invention uses rubber powder recycled from waste tires as raw material, then adds reagents to make it undergo sol-gel reaction, and uses freeze-drying technology to prepare aerogel, thereby achieving uniform dispersion and fixation of the rubber powder in three-dimensional space. The prepared aerogel has low density, high porosity and compression recovery.

[0022] The prepared aerogel has the defect of being hydrophilic, so the present invention introduces a silane modifier to hydrophobically modify it, thereby realizing a functionalized aerogel with super hydrophobicity and oleophilicity.

[0023] The prepared aerogel has a certain heat insulation function, so the present invention can add an inorganic silicon source in the subsequent optimization preparation process to further improve the thermal stability of the rubber powder, thereby improving the heat insulation performance of the prepared aerogel.

[0024] The present invention reuses rubber powder recovered from waste tires, and the prepared aerogel can be applied to the fields of heat insulation and oil absorption, making an excellent contribution to environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 These are photos showing the good dispersibility of waste rubber powder in water and actual photos of rubber aerogel prepared from waste rubber powder.

[0026] Figure 2 This is the technical route and reaction mechanism diagram for preparing rubber aerogel using waste rubber powder.

[0027] Figure 3 Photo of a rubber aerogel compression cycle.

[0028] Figure 4 This is the infrared thermal imaging image of rubber aerogel.

[0029] Figure 5 The water contact angle images of the rubber aerogel and the images immersed in water are collected.

[0030] Figure 6 Photographs of hydrophobic rubber aerogels adsorbing vacuum pump oil and dichloromethane (Sudan III staining). Specific implementation plan

[0031] The present invention is described below in conjunction with embodiments, but it is necessary to explain here that these examples are only for further elaboration of the present invention and are not limitations of the claims of the present invention. Those skilled in the art can refer to the contents of this article and make some non-essential improvements and adjustments. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all deemed to be included in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by relevant personnel without making creative work are within the scope of protection of the present invention. In the following examples, the proportions involved are all by mass.

[0032] Example 1

[0033] 1g polyvinyl alcohol, 0.5g starch, 2.5g glyoxal, 5g dispersible rubber powder of 60 mesh and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 40°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0034] Example 2

[0035] 1.25g polyethylene glycol, 0.5g starch, 2.5g glyoxal, 5g dispersible rubber powder of 60 mesh and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 50°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0036] Example 3

[0037] 1.5g hyaluronic acid, 0.5g starch, 2.5g glyoxal, 5g dispersible rubber powder of 60 mesh, and 4ml hydrochloric acid were added to water in sequence at 20°C and stirred for 3h, and then a cross-linking reaction was carried out at 60°C for 12h to obtain a hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain a rubber aerogel.

[0038] Example 4

[0039] 1.75g ​​carboxymethyl cellulose, 0.5g starch, 2.5g glyoxal, 5g dispersible rubber powder of 60 mesh, and 4ml hydrochloric acid were added to water at 20°C and stirred for 3h, and then cross-linked at 70°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0040] Example 5

[0041] 2g polyacrylamide, 0.5g pectin, 2.5g glyoxal, 5g dispersible rubber powder of 60 mesh and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 80°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0042] Example 6

[0043] 1g polyvinyl alcohol, 0.4g starch, 2.5g glutaraldehyde, 5g dispersible rubber powder of 60 mesh and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 70°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0044] Example 7

[0045] 1g polyvinyl alcohol, 0.5g xanthan gum, 2.5g glyoxal, 5g dispersible rubber powder of 60 mesh and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 70°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0046] Example 8

[0047] 1g polyvinyl alcohol, 0.6g xanthan gum, 2.5g glutaraldehyde, 5g 60 mesh dispersible rubber powder and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 70°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0048] Example 8

[0049] 1g polyvinyl alcohol, 0.7g pectin, 2.5g glyoxal, 5g 60-mesh dispersible rubber powder and 4ml hydrochloric acid were sequentially added into water at 20°C and stirred for 3h, and then cross-linked at 70°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0050] Example 9

[0051] 1g polyacrylamide, 0.4g starch, 3g glutaraldehyde, 5g dispersible rubber powder of 60 mesh and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 40°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0052] Example 10

[0053] 1g polyvinyl alcohol, 0.4g starch, 1.25g glutaraldehyde, 5g dispersible rubber powder of 60 mesh and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 40°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0054] Embodiment 11

[0055] 1g polyacrylamide, 0.4g xanthan gum, 2.5g citric acid, 5g 60 mesh dispersible rubber powder and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 40°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0056] Example 12

[0057] 1g polyacrylamide, 0.5g gelatin, 2.5g citric acid, 4g 60 mesh dispersible rubber powder and 4ml hydrochloric acid were added to water in sequence at 20°C and stirred for 3h, and then cross-linked at 40°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0058] Example 13

[0059] 1g polyacrylamide, 0.5g guar gum, 2.5g glutaraldehyde, 3g dispersible rubber powder of 60 mesh, 4ml hydrochloric acid were mixed at 20℃ The above steps are sequentially added into water and stirred for 3 h, and then cross-linked at 40 °C for 12 h to obtain a hydrogel; the hydrogel is then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel is placed in a vacuum freeze dryer at -50 °C for 72 h to obtain a rubber aerogel.

[0060] Embodiment 14

[0061] 1g polyacrylamide, 0.5g xanthan gum, 2.5g glyoxal, 2g 60 mesh dispersible rubber powder and 4ml hydrochloric acid were added into water in sequence at 20°C and stirred for 3h, and then cross-linked at 40°C for 12h to obtain hydrogel; the hydrogel was then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0062] Embodiment 15

[0063] 1g polyacrylamide, 0.5g carrageenan, 2.5g citric acid, 1g dispersible rubber powder of 60 mesh and 4ml hydrochloric acid are sequentially added into water at 20°C and stirred for 3h, and then cross-linked at 40°C for 12h to obtain hydrogel; the hydrogel is then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel is placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0064] Example 16

[0065] 1g hyaluronic acid, 0.5g xanthan gum, 2.5g citric acid, 5g 60 mesh dispersible rubber powder and 4ml sulfuric acid were added to water in sequence at 20°C and stirred for 3h, then cross-linked at 40°C for 12h to obtain hydrogel; then the hydrogel was placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72h to obtain rubber aerogel.

[0066] Embodiment 17

[0067] 1g carboxymethyl cellulose, 0.5g guar gum, 2.5g citric acid, 1g dispersible rubber powder (60 mesh), 4ml ammonia water were mixed at 20℃. The above steps are sequentially added into water and stirred for 3 h, and then cross-linked at 40 °C for 12 h to obtain a hydrogel; the hydrogel is then placed in a refrigerator or in a liquid nitrogen environment for freezing; the frozen hydrogel is placed in a vacuum freeze dryer at -50 °C for 72 h to obtain a rubber aerogel.

[0068] Embodiment 18

[0069] 1g polyvinyl alcohol, 0.5g starch, 2.5g glyoxal, 5g 60 mesh dispersible rubber powder, and 4ml sulfuric acid were added to water at 20℃ and stirred for 3h, and then cross-linked at 70℃ for 12h to obtain hydrogel; then the hydrogel was placed in a refrigerator or liquid nitrogen environment for freezing; the frozen hydrogel was placed in a vacuum freeze dryer at -60℃ for 72h to obtain rubber aerogel. The prepared aerogel was placed in a sealed container, and a small glass bottle containing a silane modifier was placed, and chemical vapor deposition technology was used at 80℃ The mixture was kept warm for 8 h, and then taken out and dried for 2 h to form a hydrophobic layer on the surface of the rubber aerogel, thereby obtaining a hydrophobic rubber aerogel.

[0070] Embodiment 19

[0071] The thermal insulation performance of the prepared rubber aerogel is optimized by using an inorganic silicon source. The inorganic silicon source is added to any of the above embodiments. Stirring at 20° C. for 3 hours to perform a cross-linking reaction to obtain a hydrogel; placing the hydrogel in a refrigerator or in a liquid nitrogen environment to freeze; The frozen hydrogel was placed in a vacuum freeze dryer at -50°C for 72 hours to obtain a rubber aerogel with thermal insulation properties.

[0072] The above is only a preferred specific implementation case of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. For those skilled in the art, improvements or equivalent substitutions are made without departing from the principle of the present invention, and these improvements and equivalent substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a rubber aerogel, characterized in that: The steps are as follows: Add a binder, a dispersant, a crosslinking agent, a dispersible rubber powder prepared in the laboratory, and a catalyst into water in sequence at 20-80°C and stir for 2-8 hours, and then perform a crosslinking reaction to obtain a hydrogel; Freeze the hydrogel in a refrigerator or under liquid nitrogen conditions; The frozen hydrogel is placed in a vacuum freeze dryer to obtain the rubber aerogel.

2. The method for preparing a rubber aerogel according to claim 1, characterized in that: The mass ratio of the binder, dispersant, crosslinking agent, dispersible rubber powder and catalyst is (0.2-1):(0.1-0.6):(1-10):(1-20):(2-20).

3. The method for preparing a rubber aerogel according to claim 1, characterized in that: The binder is a mixture of one or more of epoxy resin matrix, polyvinyl alcohol, polyethylene glycol, polyacrylamide, phenolic resin, silicone emulsion, styrene acrylic emulsion, hyaluronic acid, silk fibroin, chitosan, konjac glucomannan and carboxymethyl cellulose.

4. The method for preparing a rubber aerogel according to claim 1, characterized in that: The dispersant is a mixture of one or more of starch, xanthan gum, gelatin, agar, carrageenan, guar gum, pectin, dextrin and sodium alginate.

5. The method for preparing a rubber aerogel according to claim 1, characterized in that: The cross-linking agent is a mixture of one or more of glyoxal, glutaraldehyde, boric acid, citric acid, genipin, sodium tetraborate and oxalic acid.

6. The method for preparing a rubber aerogel according to claim 1, characterized in that: The laboratory dispersible rubber powder is a mixture of one or more of natural rubber, styrene-butadiene rubber, butadiene rubber or isoprene rubber, and is also accompanied by some residual nylon fibers.

7. The method for preparing a rubber aerogel according to claim 1, characterized in that: The catalyst is one or more of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, sodium hydroxide, potassium hydroxide, and ammonia water.

8. The method for preparing a rubber aerogel according to claim 1, characterized in that: The temperature of the cross-linking reaction is 40-90° C. and the time is 2-12 hours.

9. The method for preparing a rubber aerogel according to claim 1, characterized in that: The cold trap temperature of the freeze drying is -50 to -80°C, and the time is 12 to 96 hours.

10. The rubber aerogel obtained by the preparation method according to any one of claims 1 to 9.

11. The use of the rubber aerogel according to claim 10, characterized in that: Used in thermal insulation, hydrophobic and oleophilic applications.

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