CN105017565A - Preparation method of graphene oxide shell coated sulfur microcapsule - Google Patents

Abstract

The invention discloses a preparation method of coated sulfur which can be used as a rubber vulcanizing agent. Using sulfur with different particle sizes as the capsule core, graphene oxide and functionalized graphene oxide as the coating material, the coated sulfur product was prepared by solution blending method. The coating process is simple, safe and environmentally friendly. Compared with the general The microcapsule coating method is simpler and simpler. The coated sulfur product prepared by the invention can be well mixed with the rubber in the mixing stage, does not spray frost in the cooling and parking stage, can release sulfur to participate in the vulcanization reaction at the vulcanization temperature, and can be used as a new type of vulcanizing agent for rubber-related industries. In addition, different functionalized GO shell materials can provide different properties, which are suitable for the development of a multifunctional vulcanizing agent.

Description

A kind of preparation method of graphene oxide shell material coating sulfur microcapsule

technical field

The invention belongs to a preparation method of coated sulfur which can be used as a novel rubber vulcanizing agent, in particular to a preparation method of graphene oxide and functionalized graphene oxide coated sulfur.

Background technique

Sulfur, as a vulcanizing agent in rubber, can endow long-chain macromolecules with a cross-linked network structure during the vulcanization stage and provide the strength required for vulcanized rubber. It is the most commonly used vulcanizing agent in the rubber industry. However, in actual use, due to the high operating temperature in the mixing and vulcanization stages, evenly mixed sulfur in the rubber compound will precipitate on the surface in the form of crystals due to the decrease in solubility during the low-temperature parking stage, resulting in "blooming". In order to solve blooming, insoluble sulfur products and sulfur microcapsule products were proposed respectively. Insoluble sulfur is a long-chain structure formed by ring-opening polymerization of sulfur. It will not precipitate after mixing in rubber. However, its high cost and high risk have also limited its industrial development. Sulfur microcapsules are a kind of core-shell structure micro-container with sulfur bounded inside by the outer coating material. During the mixing stage, due to the existence of the shell material, it can form a good miscibility with rubber, and it does not spray frost during the parking stage. It is a new type of vulcanizing agent that can release sulfur to participate in the reaction at the vulcanization temperature. At present, the shell materials used for its coating are some traditional shell materials, such as urea-formaldehyde resin, melamine resin, polyurea, etc. The introduction of shell materials may affect

Graphene is a single atomic layer two-dimensional structure formed by ^sp2 hybridization of six carbon atoms, and the hexagonal rings form a honeycomb structure. Simply put, graphene is a single layer of graphite. Single-layer graphene exists in a two-dimensional crystal structure with a thickness of only 0.334nm. It is the basic unit for building other carbon materials. It can be wrapped to form zero-dimensional fullerenes, and rolled up to form one-dimensional carbon nanotubes. Layers stack to form three-dimensional graphite. Graphene has aroused great interest among scientific and technological workers due to its high specific surface area, outstanding thermal conductivity and mechanical properties, and its extraordinary electron transport properties. Graphene has very good mechanical properties and is the strongest material known to man. The Young's tensile modulus can be as high as 1100GPa, and the breaking strength can be as high as 125GPa.

The surface of graphene is stable and inert, and it is easy to stack together. It cannot achieve the excellent performance of single-layer graphene. In order to improve its dispersion and application range, we can functionalize graphene oxide. The main methods are non-covalent Bond functionalization and covalent bond functionalization. Functionalized graphene or graphene oxide not only improves the solvent dispersion performance, but also endows graphene with new properties and expands its application fields.

Contents of the invention

The invention discloses a preparation method of coated sulfur which can be used as a rubber vulcanizing agent. Using sulfur with different particle sizes as the capsule core, graphene oxide and functionalized graphene oxide as the coating material, the coated sulfur product was prepared by solution blending method. The coating process is simple, safe and environmentally friendly. Compared with the general The microcapsule coating method is simpler and simpler. The coated sulfur product prepared by the invention can be well mixed with the rubber in the mixing stage, does not spray frost in the cooling and parking stage, can release sulfur to participate in the vulcanization reaction at the vulcanization temperature, and can be used as a new type of vulcanizing agent for rubber-related industries. In addition, different functionalized GO shell materials can provide different properties, which are suitable for the development of a multifunctional vulcanizing agent.

Using the formula and process provided by this patent, graphene oxide and surface functionalized graphene oxide are used as coating materials to coat sulfur. The obtained coated sulfur product is gray powder, and the mass fraction of sulfur is 90%. Above, the coating rate is extremely high, and different coating materials improve the compactness of sulfur microcapsules, and compared with other methods, the obtained product does not require post-treatment such as extraction, which is safe and environmentally friendly. It can be used as a rubber vulcanizing agent and can effectively inhibit The phenomenon of "blooming" is a kind of rubber vulcanizing agent with development value.

Description of drawings

The attached picture is a scanning electron microscope photo of the surface morphology of graphene oxide-coated sulfur microcapsules

Detailed ways

The following specific examples explain in detail the invented graphene oxide and functionalized graphene oxide shell-coated sulfur microcapsules and their preparation methods. However, these examples do not limit the scope of the present invention, nor should it be understood that only the conditions, parameters or values provided by the present invention can implement the present invention.

Example 1

The composition and consumption of raw materials for preparing single-layer graphene oxide-coated sulfur are as follows:

The preparation method of graphene oxide coated sulfur is as follows:

(1) Add 0.9927g sodium thiosulfate pentahydrate to the aqueous solution containing 0.05g PVP and 2.5ml graphene oxide dispersion at room temperature, after it dissolves, add 0.8ml dilute hydrochloric acid dropwise, then stir the reaction at room temperature 3 hour, prepared sulfur aqueous dispersion;

(2) The prepared coated sulfur is subjected to suction filtration, washed with water and alcohol for three times, and dried in an oven for 12 hours to obtain a graphene oxide membrane coated sulfur product.

The coated sulfur prepared by the method of the present invention is tested and analyzed by DLS and SEM, and it can be seen that the particle size of the product is about 0.8-2.4 μm, a large amount of agglomeration occurs, and the mass fraction of sulfur is 97.1%.

Example 2

The composition and consumption of raw materials for preparing single-layer graphene oxide-coated sulfur are as follows:

The preparation method of graphene oxide coated sulfur is as follows:

(1) Add 0.9927g sodium thiosulfate pentahydrate to the aqueous solution containing 0.05gPVA and 5ml graphene oxide dispersion at room temperature, after it dissolves, add 0.8ml dilute hydrochloric acid dropwise, then stir and react at room temperature for 3 hours , prepare the sulfur aqueous dispersion;

(2) The prepared coated sulfur is subjected to suction filtration, washed with water and alcohol for three times, and dried in an oven for 12 hours to obtain a graphene oxide membrane coated sulfur product.

The coated sulfur prepared by the method of the present invention is tested and analyzed by DLS and SEM, and it can be seen that the particle size of the product is about 0.5-1.2 μm, and the mass fraction of sulfur is 96.0%.

Example 3

The composition and consumption of raw materials for preparing single-layer graphene oxide-coated sulfur are as follows:

The preparation method of polyvinyl alcohol modified graphene oxide coated sulfur is as follows:

(1) Add 0.9927g sodium thiosulfate pentahydrate to the 200ml aqueous solution containing 0.05gPVP and 12.5ml polyvinyl alcohol modified graphene oxide dispersion at room temperature, after it dissolves, add 0.8ml dilute hydrochloric acid dropwise, then Stirring and reacting at room temperature for 3 hours to prepare a sulfur water dispersion;

(2) The prepared coated sulfur is subjected to suction filtration, washed with water and alcohol for three times, and dried in an oven for 12 hours to obtain a graphene oxide membrane coated sulfur product.

The coated sulfur prepared by the method of the present invention is tested and analyzed by DLS and SEM electron microscope. It can be seen that the particle size of the product is about 3.5-8.0 μm, the agglomeration phenomenon is basically eliminated, and the mass fraction of sulfur is 93.6%.

Example 4

The composition and consumption of raw materials for preparing single-layer graphene oxide-coated sulfur are as follows:

The preparation method of ethylenediamine modified graphene oxide coated sulfur is as follows:

(1) Add 4.9636g sodium thiosulfate pentahydrate to the aqueous solution containing 0.05gPVA and 10ml ethylenediamine-modified graphene oxide dispersion at room temperature, after it dissolves, add 4ml dilute hydrochloric acid dropwise, and then Stirring and reacting for 3 hours, a sulfur water dispersion was prepared;

(2) The prepared coated sulfur is subjected to suction filtration, washed with water and alcohol for three times, and dried in an oven for 12 hours to obtain a graphene oxide membrane coated sulfur product.

The coated sulfur prepared by the method of the present invention is tested and analyzed by DLS and SEM, and it can be seen that the particle size of the product is about 4.3-10.2 μm, and the mass fraction of sulfur is 94.7%.

Example 5

The raw material composition and dosage of graphene oxide membrane coated sulfur are as follows:

The preparation method of multilayer film graphene oxide coating sulfur is as follows:

(1) Add 0.9927g sodium thiosulfate pentahydrate to the aqueous solution containing 0.05gPVP and 5ml triethyldiamine graphene oxide dispersion at room temperature, after it dissolves, add 0.8ml dilute hydrochloric acid dropwise, and then Stirring and reacting for 3 hours, the sulfur aqueous dispersion was prepared;

(2) The prepared coated sulfur is subjected to suction filtration, washed with water and alcohol for three times, and dried in an oven for 12 hours to obtain a graphene oxide membrane coated sulfur product.

The coated sulfur prepared by the method of the present invention is tested and analyzed by DLS and SEM, and it can be seen that the particle size of the product is about 0.5-1.2 μm, and the mass fraction of sulfur is 92.6%.

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art can still understand the foregoing embodiments. Modifications are made to the technical solutions described, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions claimed in the present invention.

Claims (8)

1. a kind of preparation method that can be used as the coated sulfur of rubber vulcanizing agent, its preparation steps are as follows: Take 2.5ml~25ml aqueous solution of graphene oxide or surface functional group modified graphene oxide, add water to 200ml, ultrasonically disperse for 30 minutes, continue to add 0.9927g~9.9272g sodium thiosulfate pentahydrate, stir and dissolve at room temperature, add dropwise mass fraction 0.8ml-4ml of 37% hydrochloric acid, react at room temperature for 3 hours, filter with suction, wash with water three times, and dry in vacuum for 12 hours to obtain graphene oxide or functional group-modified graphene oxide-coated sulfur microcapsules. 2. The preparation method according to claim 1, characterized in that: the prepared coated sulfur capsule wall material is graphene oxide and functional group modified graphene oxide. 3. The preparation method according to claim 1, characterized in that: the prepared sulfur-coated capsule wall material graphene oxide is prepared by the traditional Hummers method. 4. The preparation method according to claim 1, characterized in that: the prepared sulfur-coated capsule wall material surface-modified graphene oxide is graphene oxide whose surface is modified by amino group and polyvinyl alcohol. 5. The preparation method according to claim 1, characterized in that: the prepared coated sulfur surfactant is polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol and the like. 6. The preparation method according to claim 1, characterized in that: the prepared coated sulfur has a particle size of 0.5-15 μm. 7. The preparation method according to claim 1, characterized in that: the wall material functionalization of the prepared coated sulfur can improve the anti-scorch or anti-aging properties of the rubber. 8. The preparation method according to claim 1, characterized in that: the coating rate of the prepared coated sulfur is above 90%.