A surface modification method for core-shell structured inorganic powder

Abstract

The invention discloses a surface modification method for a core-shell structure inorganic powder, and the step includes: taking the core-shell structure inorganic powder, soaking in a hydrofluoric acid solution for 1 5h, then placing the soaking system in 180 220 DEG C and keeping it warm for 20 50h, separating and drying the solid material and washing it with deionized water, then annealing the solid material at 520 550 DEG C, in an argon atmosphere for 1.8 2.5h to obtain intermediate A; taking intermediate A to be mixed in an organic solvent, then adding a silane coupling agent, and obtaining intermediate B through stirring reaction; taking intermediate B to be mixed in an organic solvent, then adding polyethyleneimine, and obtaining intermediate C through stirring reaction; taking intermediate C, through separation and drying. The present invention is directed to the core-shell structure inorganic powder, and before it carries out silane coupling agent and polyethyleneimine modification treatment, it is first soaked in hydrofluoric acid for heat preservation treatment, then annealing treatment is carried out so that the powder surface structure is improved, and wettability is improved, and it is conducive to dispersion, and the applicable environment of the increase powder is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic powders, and in particular to a surface modification method of inorganic powders with a core-shell structure. Background Art

[0002] Inorganic powders, mainly including calcium carbonate, calcium oxide, calcium hydroxide, aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium carbonate, magnesium oxide, brucite, dolomite, calcite, etc., have been widely used and developed in many fields. For example, they are used as plastic fillers, which have a great promoting effect on the performance and process of plastics. Core-shell structure materials are composite materials with an ordered assembly structure formed by chemical bonds or other interactions. They are generally composed of a central core and a shell layer coated on the outside. Compared with a single material, core-shell structure materials have unique structural characteristics. They integrate the properties of the two materials inside and outside, and complement each other's respective deficiencies, and have great research value. Accordingly, many types of inorganic powders with core-shell structures have appeared on the market, such as the common inorganic powder / SiO2 core-shell structure composite powder.

[0003] Inorganic powder / SiO2 core-shell composite powders have a disadvantage: poor surface wettability, which makes them difficult to disperse, thus limiting their application. To address this, surface modification of the composite powder is necessary. Summary of the Invention

[0004] The purpose of the present invention is to provide a surface modification method for a core-shell structured inorganic powder, which solves the problem of poor surface wettability of the existing core-shell structured inorganic powder.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] A surface modification method for a core-shell structured inorganic powder comprises the following steps:

[0007] S1. Take a core-shell structure inorganic powder and soak it in a hydrofluoric acid solution with a mass concentration of 5-20% for 1-5 hours. Then, place the soaking system at 180-220°C and keep it for 20-50 hours. Separate the solid material, wash it with deionized water, and dry it. Then, anneal the solid material at 520-550°C in an argon atmosphere for 1.8-2.5 hours to obtain intermediate A.

[0008] S2, taking the intermediate A and mixing it in an organic solvent, then adding a silane coupling agent, and reacting at 50-70° C. with stirring to obtain the intermediate B;

[0009] S3, taking the intermediate B and mixing it in an organic solvent, then adding polyethyleneimine, and reacting at 50-70° C. with stirring to obtain intermediate C;

[0010] S4. Take the intermediate C, separate it and dry it.

[0011] A further improvement is that the core-shell structured inorganic powder refers to an inorganic powder / SiO2 core-shell structured composite powder, and the inorganic powder is selected from one of calcium carbonate, calcium oxide, calcium hydroxide, aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium carbonate, magnesium oxide, brucite, dolomite or calcite.

[0012] A further improvement is that the silane coupling agent is selected from one of vinyltriethoxysilane, vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, and vinyltri(β-methoxyethoxy)silane.

[0013] A further improvement is that the mass ratio of the silane coupling agent to the intermediate A is 1:1-3.

[0014] A further improvement is that the organic solvent is one of methanol, ethanol or propylene glycol.

[0015] A further improvement is that the mass ratio of the polyethyleneimine to the intermediate B is 2:1-4.

[0016] The beneficial effect of the present invention is that: before the core-shell structured inorganic powder is modified with a silane coupling agent and polyethyleneimine, it is first immersed in hydrofluoric acid for heat preservation treatment, and then annealed, so that the surface structure of the powder is improved, the wettability is enhanced, it is conducive to dispersion, and the applicable environment of the powder is increased. DETAILED DESCRIPTION

[0017] The present application is further described in detail below in conjunction with the embodiments. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0018] Example 1

[0019] A surface modification method for a core-shell structured inorganic powder comprises the following steps:

[0020] S1. Soak calcium carbonate / SiO2 core-shell composite powder in a 5% hydrofluoric acid solution for 5 hours, then heat the immersion system at 180°C for 50 hours, separate the solid material, wash it with deionized water, and dry it. Then, anneal the solid material at 520°C in an argon atmosphere for 2.5 hours to obtain intermediate A.

[0021] S2. Take the intermediate A and mix it with 10 times the mass of methanol, then add vinyltriethoxysilane, the mass ratio of vinyltriethoxysilane to intermediate A is 1:1, and react at 50° C. with stirring for 2 hours to obtain intermediate B;

[0022] S3, taking the intermediate B and mixing it with 10 times the weight of methanol, then adding polyethyleneimine, the mass ratio of polyethyleneimine to intermediate B is 2:1, and reacting at 50° C. with stirring for 2 hours to obtain intermediate C;

[0023] S4. Take the intermediate C, separate it and dry it.

[0024] Example 2

[0025] A surface modification method for a core-shell structured inorganic powder comprises the following steps:

[0026] S1. Soak calcium carbonate / SiO2 core-shell composite powder in a 10% hydrofluoric acid solution for 3 hours, then heat the immersion system at 200°C for 35 hours, separate the solid material, wash it with deionized water, and dry it. Then, anneal the solid material at 530°C in an argon atmosphere for 2 hours to obtain intermediate A.

[0027] S2. Take the intermediate A and mix it with 10 times the mass of ethanol, then add vinyltrimethoxysilane, the mass ratio of vinyltrimethoxysilane to intermediate A is 1:2, and react at 60° C. with stirring for 3 hours to obtain intermediate B;

[0028] S3, taking the intermediate B and mixing it with 10 times the mass of ethanol, then adding polyethyleneimine, the mass ratio of polyethyleneimine to intermediate B is 1:1, and reacting at 60°C with stirring for 3 hours to obtain intermediate C;

[0029] S4. Take the intermediate C, separate it and dry it.

[0030] Example 3

[0031] A surface modification method for a core-shell structured inorganic powder comprises the following steps:

[0032] S1. Soak alumina / SiO2 core-shell composite powder in a 20% hydrofluoric acid solution for 1 hour. Then, heat the immersion system at 220°C for 20 hours. Separate the solid material, wash it with deionized water, and dry it. Then, anneal the solid material at 550°C in an argon atmosphere for 1.8 hours to obtain intermediate A.

[0033] S2. The intermediate A is mixed with ethanol, and methacryloxypropyltrimethoxysilane is added, with the mass ratio of methacryloxypropyltrimethoxysilane to intermediate A being 1:3, and the mixture is stirred at 70° C. to obtain intermediate B;

[0034] S3, taking the intermediate B and mixing it with ethanol, then adding polyethyleneimine, the mass ratio of polyethyleneimine to intermediate B is 1:2, and reacting at 70° C. with stirring to obtain intermediate C;

[0035] S4. Take the intermediate C, separate it and dry it.

[0036] Comparative Example 1

[0037] A surface modification method for a core-shell structured inorganic powder comprises the following steps:

[0038] S1. Soak calcium carbonate / SiO2 core-shell composite powder in a 10% hydrofluoric acid solution for 3 hours, then heat the immersion system at 200°C for 35 hours, separate the solid material, wash it with deionized water, and dry it to obtain intermediate A.

[0039] S2. Take the intermediate A and mix it with 10 times the mass of ethanol, then add vinyltrimethoxysilane, the mass ratio of vinyltrimethoxysilane to intermediate A is 1:2, and react at 60° C. with stirring for 3 hours to obtain intermediate B;

[0040] S3, taking the intermediate B and mixing it with 10 times the mass of ethanol, then adding polyethyleneimine, the mass ratio of polyethyleneimine to intermediate B is 1:1, and reacting at 60°C with stirring for 3 hours to obtain intermediate C;

[0041] S4. Take the intermediate C, separate it and dry it.

[0042] Comparative Example 2

[0043] A surface modification method for a core-shell structured inorganic powder comprises the following steps:

[0044] S1. Take calcium carbonate / SiO2 core-shell structure composite powder and anneal it at 530℃ in argon atmosphere for 2h to obtain intermediate A;

[0045] S2. Take the intermediate A and mix it with 10 times the mass of ethanol, then add vinyltrimethoxysilane, the mass ratio of vinyltrimethoxysilane to intermediate A is 1:2, and react at 60° C. with stirring for 3 hours to obtain intermediate B;

[0046] S3, taking the intermediate B and mixing it with 10 times the mass of ethanol, then adding polyethyleneimine, the mass ratio of polyethyleneimine to intermediate B is 1:1, and reacting at 60°C with stirring for 3 hours to obtain intermediate C;

[0047] S4. Take the intermediate C, separate it and dry it.

[0048] Comparative Example 3

[0049] A surface modification method for a core-shell structured inorganic powder comprises the following steps:

[0050] S1. Calcium carbonate / SiO2 core-shell structure composite powder was mixed with 10 times the mass of ethanol, and vinyltrimethoxysilane was added. The mass ratio of vinyltrimethoxysilane to intermediate A was 1:2. The mixture was stirred at 60°C for 3 hours to obtain intermediate A.

[0051] S2. The intermediate A is mixed with 10 times the mass of ethanol, and polyethyleneimine is added, with the mass ratio of polyethyleneimine to intermediate A being 1:1. The mixture is stirred and reacted at 60° C. for 3 h to obtain intermediate C;

[0052] S3. Take the intermediate B, separate it and dry it.

[0053] Comparative Example 4

[0054] A surface modification method for a core-shell structured inorganic powder comprises the following steps:

[0055] S1. Calcium carbonate / SiO2 core-shell structure composite powder was mixed with 10 times the mass of ethanol, and vinyltrimethoxysilane was added, with the mass ratio of vinyltrimethoxysilane to intermediate A being 1:2. The mixture was stirred at 60°C for 3 hours to obtain intermediate A.

[0056] S2. The intermediate A is mixed with 10 times the mass of ethanol, and polyethyleneimine is added, with the mass ratio of polyethyleneimine to intermediate A being 1:1. The mixture is stirred and reacted at 60° C. for 3 h to obtain intermediate B;

[0057] S3, taking the intermediate B, soaking it in a 10% hydrofluoric acid solution for 3 hours, then keeping the soaking system at 200°C for 35 hours, separating the solid material, washing it with deionized water, and drying it, and then annealing the solid material at 530°C in an argon atmosphere for 2 hours to obtain intermediate C;

[0058] S4. Take the intermediate C, separate it and dry it.

[0059] The surface-modified calcium carbonate / SiO2 core-shell composite powders of Examples 1-3 and Comparative Examples 1-4, as well as the unmodified calcium carbonate / SiO2 core-shell composite powders, were measured for water contact angle using an optical contact angle / interfacial tension SL200KS contact angle meter authorized by Kono Industries, Inc., USA. The measured results were:

[0060] Example 1: 28.2°, showing hydrophilicity;

[0061] Example 2: 28.1°, showing hydrophilicity;

[0062] Example 3: 27.4°, showing hydrophilicity;

[0063] Comparative Example 1: 78.6°, showing hydrophilicity;

[0064] Comparative Example 2: 62.5°, showing hydrophilicity;

[0065] Comparative Example 3: 98.5°, showing hydrophobicity;

[0066] Comparative Example 4: 49.9°, showing hydrophilicity;

[0067] Blank group: 103.9°, indicating hydrophobicity.

[0068] It can be seen from the above test results that the calcium carbonate / SiO2 core-shell structure composite powder after surface modification treatment in Examples 1-3 of the present invention has a water contact angle of less than 30°, which has good wettability, while the blank group without surface modification treatment has a water contact angle of 103.9°, which shows hydrophobicity; and since Comparative Example 1 omits annealing treatment, and Comparative Example 2 omits hydrofluoric acid immersion and heat preservation treatment, both increase the water contact angle and decrease the wettability. Comparative Example 3 omits both hydrofluoric acid immersion and heat preservation treatment and annealing treatment, which further increases the water contact angle and shows hydrophobicity, indicating that hydrofluoric acid immersion and heat preservation treatment and annealing treatment play a key role in improving wettability; and Comparative Example 5 places the hydrofluoric acid immersion and heat preservation treatment and annealing treatment steps after the silane coupling agent and polyethyleneimine modification treatment, resulting in the water contact angle being increased to 49.9°, and the wettability is also reduced to a certain extent compared with Examples 1-3.

[0069] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A surface modification method for a core-shell structured inorganic powder, characterized in that the steps include: S1. Take an inorganic powder / SiO2 core-shell structure composite powder, soak it in a hydrofluoric acid solution with a mass concentration of 5-20% for 1-5 hours, then place the soaking system at 180-220°C and keep it warm for 20-50 hours, separate the solid material, wash it with deionized water, and then dry it. Then, anneal the solid material at 520-550°C in an argon atmosphere for 1.8-2.5 hours to obtain an intermediate A; wherein the inorganic powder / SiO2 core-shell structure composite powder is selected from calcium carbonate / SiO2 core-shell structure composite powder; S2, taking the intermediate A and mixing it in an organic solvent, then adding a silane coupling agent, and reacting at 50-70° C. with stirring to obtain the intermediate B; S3, taking the intermediate B and mixing it in an organic solvent, then adding polyethyleneimine, and reacting at 50-70° C. with stirring to obtain intermediate C; S4. Take the intermediate C, separate it and dry it.

2. The surface modification method of a core-shell structured inorganic powder according to claim 1, characterized in that: In step S1, the inorganic powder / SiO2 core-shell structure composite powder is selected from alumina / SiO2 core-shell structure composite powder.

3. The surface modification method of a core-shell structured inorganic powder according to any one of claims 1-2, characterized in that: The silane coupling agent is selected from one of vinyl triethoxysilane, vinyl trimethoxysilane, methacryloxypropyl trimethoxysilane and vinyl tri(β-methoxyethoxy) silane.

4. The surface modification method of a core-shell structured inorganic powder according to any one of claims 1-2, characterized in that: The mass ratio of the silane coupling agent to the intermediate A is 1:1-3.

5. The surface modification method of a core-shell structured inorganic powder according to any one of claims 1-2, characterized in that: The organic solvent is one of methanol, ethanol or propylene glycol.

6. A surface modification method for a core-shell structured inorganic powder according to any one of claims 1-2, characterized in that: The mass ratio of the polyethyleneimine to the intermediate B is 2:1-4.