Agglomerate-based super-infiltration titanium dioxide as well as preparation method and application thereof

Abstract

The invention discloses super-infiltrated titanium dioxide based on an aggregate as well as a preparation method and application of the super-infiltrated titanium dioxide, and belongs to the technical field of nano materials. The preparation method comprises the following steps: adding inorganic coated titanium dioxide into a sodium polyacrylate solution, carrying out a first stirring reaction, then adding a polyacrylamide solution or a polymethylacryloyloxyethyl trimethyl ammonium chloride solution, carrying out a second stirring reaction, and carrying out a second stirring reaction to obtain the super-infiltrated titanium dioxide based on the condensate. And drying the aggregate phase, and crushing to obtain the aggregate-based super-infiltrated titanium dioxide. The prepared super-infiltration titanium dioxide based on the condensate shows super infiltration to solvents such as normal hexane with low surface tension and water with high surface tension (the contact angle is 0 degree, namely, the super-infiltration titanium dioxide shows super infiltration to hydrophobic and hydrophilic surfaces).

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanomaterials, in particular to a super-wetting titanium dioxide based on condensate and a preparation method and application thereof. BACKGROUND

[0002] Titanium dioxide is a white inorganic filler with high hiding power, which is often added as a white pigment to coatings, plastics, rubber, fabrics, inks, ceramics, separation membranes, medicines, cosmetics and other materials. However, titanium dioxide has high photocatalytic activity, is prone to yellowing and agglomeration, so organic coating methods are often used to improve the weather resistance of titanium dioxide and its wettability with plastic substrates.

[0003] Currently commonly used organic coating agents include 2-phosphono-2-hydroxy-1,1-ethanedioic acid and its derivatives, 3-aminopropyltriethoxysilane, trimethylolpropane, oligomeric ethylene glycol, oligomeric glycerol and its derivatives, etc. The interaction between the titanium dioxide and the substrate is weak, such as van der Waals force and hydrogen bond, which cannot well solve the problems of poor dispersibility and wettability of titanium dioxide, and often cannot adapt to different structures of the substrate (such as PE, PP, PS, PET and polyamide having different surface tension and compatibility), resulting in problems such as agglomeration of titanium dioxide, stress concentration and decrease of tensile strength.

[0004] Therefore, how to solve the problem of interface wettability of titanium dioxide and substrates with different surface tension, and further improve the whiteness, weather resistance, mechanical properties, corrosion resistance of the material, and reduce the preparation cost of the material, has become a technical problem to be solved by those skilled in the art. SUMMARY

[0005] The purpose of the present application is to provide a super-wetting titanium dioxide based on condensate and a preparation method and application thereof, to solve the problems existing in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0007] One of the technical solutions of the present application is a preparation method of a super-wetting titanium dioxide based on condensate, comprising the following steps:

[0008] The inorganic coated titanium dioxide is added to a sodium polyacrylate solution, and a first stirring reaction is carried out, then a polyacrylamide solution or a polymethylacryloyloxyethyltrimethylammonium chloride solution is added, and a second stirring reaction is carried out, and the condensate phase is dried and crushed to obtain the super-wetting titanium dioxide based on condensate.

[0009] Preferably, the inorganic coated titanium dioxide includes Al2O3 and SiO2 coated titanium dioxide.

[0010] Preferably, the mass of the Al2O3 is 3-5% of the mass of the inorganically coated titanium dioxide, more preferably 3.61%;

[0011] The mass of SiO2 is 1 to 2.5% of the mass of the inorganically coated titanium dioxide, more preferably 1.55%;

[0012] The diameter of the titanium dioxide is 200-300 nm.

[0013] More preferably, the titanium dioxide includes rutile titanium dioxide.

[0014] Preferably, the concentration of the sodium polyacrylate solution is 5-10 wt%.

[0015] The concentration of the polyacrylamide solution is 5-10 wt%.

[0016] The concentration of the polymethacryloyloxyethyltrimethylammonium chloride solution is 5–10 wt%.

[0017] Preferably, when the substance added after the first stirring reaction is a polyacrylamide solution, the total mass of sodium polyacrylate in the sodium polyacrylate solution and polyacrylamide in the polyacrylamide solution is 0.5 to 7% of the mass of the inorganically coated titanium dioxide.

[0018] More preferably, the solvents in the sodium polyacrylate solution and the polyacrylamide solution are both aqueous solutions with a pH of 5 to 10, and the pH of the solution is adjusted by hydrochloric acid and sodium hydroxide solution.

[0019] Preferably, the molecular weight of the sodium polyacrylate is 4000-6000 g / mol;

[0020] The polyacrylamide has a molecular weight of 5000-8000 g / mol and an ionicity of 20-50%.

[0021] More preferably, the polyacrylamide is one of anionic polyacrylamide, neutral polyacrylamide, and cationic polyacrylamide.

[0022] Preferably, the mass of the sodium polyacrylate is 20-60% of the total mass of sodium polyacrylate and polyacrylamide.

[0023] Preferably, the first stirring reaction time is 0.5 to 1 hour;

[0024] The second stirring reaction takes 0.5 to 2 hours.

[0025] When the two polymers (sodium polyacrylate and polyacrylamide) are mixed, they separate into a cohesive phase and a supernatant. The cohesive phase is a viscous solid at the bottom, containing a complex of polyacrylate and polyacrylamide, and coating titanium dioxide. Inorganic counterions from both polymers are expelled (driven by entropy increase) into the supernatant. Sodium polyacrylate accounts for 20–60% of the total mass of the organic coating agents (sodium polyacrylate and polyacrylamide). A suitable ratio of sodium polyacrylate to polyacrylamide (20–60% : 40–80%) must be maintained; otherwise, the polymers will enter the supernatant, and inorganic ions will not be effectively expelled from the cohesive phase.

[0026] The aggregate formed by the composite of two polymers (sodium polyacrylate and polyacrylamide) used in this invention can reduce surface energy through the discontinuous micro-regions of its polar (ionic region) and non-polar (polymer skeleton), resulting in stronger wettability and adhesion to both polar and non-polar surfaces. While efficiently dispersing titanium dioxide, the two polymers also enable the prepared superwetting titanium dioxide to exhibit superwetting properties on surfaces of different polarities, thereby improving the interfacial force between the superwetting titanium dioxide and the polymer substrate, resulting in better dispersion. Compared with commercially available organic-coated titanium dioxide, it shows significant advantages in whiteness and mechanical properties.

[0027] The second technical solution of the present invention: a superwetting titanium dioxide based on aggregates prepared by the above preparation method.

[0028] The third technical solution of the present invention: the application of the above-mentioned superwetting titanium dioxide based on aggregates in the preparation of plastics, fibers, rubber, coatings, inks, paper, cosmetics, separation films or pharmaceuticals.

[0029] The present invention discloses the following technical effects:

[0030] (1) The superwetting titanium dioxide based on aggregates prepared in this invention exhibits superwetting properties (contact angle of 0°, i.e., superwetting properties on both hydrophobic and hydrophilic surfaces) to solvents ranging from low surface tension n-hexane to high surface tension water. This indicates that the superwetting titanium dioxide prepared in this invention has the potential to be applied to different plastic substrates and exhibits good wettability and applicability to different plastic substrates, which can make up for the shortcomings of existing titanium dioxide.

[0031] (2) The present invention uses a new combination of organic coating agents (sodium polyacrylate and polyacrylamide) based on composite aggregates to organically coat titanium dioxide, so that the titanium dioxide coating is dispersed in the organic coating agent, thereby improving the wettability of titanium dioxide to different substrates.

[0032] The composite aggregate is formed by combining sodium polyacrylate and polyacrylamide. The main interaction between the aggregates is electrostatic interaction, combined with multiple hydrogen bonds and van der Waals forces, forming a low surface tension phase.

[0033] (3) Compared with existing titanium dioxide-doped plastic composites, the titanium dioxide-doped plastic composites prepared by the present invention based on aggregate-based super-wetting titanium dioxide have more uniform dispersion of titanium dioxide, resulting in better mechanical properties and higher whiteness values.

[0034] (4) The preparation method of the present invention has simpler equipment requirements, milder processing conditions, lower process and raw material costs, and does not use small molecule organic matter, resulting in no VOC pollution, while exhibiting significant performance advantages. In addition, due to the high compatibility of the aggregate structure with guest molecules (i.e., dyes and inorganic and organic nanoparticles, etc.), it can enrich and retain high concentrations of dye molecules, antibacterial components, etc., providing a carrier for further functionalization of titanium dioxide. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 The contact angles of the superwetting titanium dioxide film prepared for Example 1 with solvents of different polarities are shown, where (A) is water and (B) is n-hexane.

[0037] Figure 2 The characterization results of titanium dioxide doped with PVC1 and titanium dioxide doped with PVC2 prepared for Example 2 are shown in the figure. (A) is a cross-sectional SEM image of titanium dioxide doped with PVC1, (B) is an EDS elemental distribution map of titanium dioxide doped with PVC1, (C) is a cross-sectional SEM image of titanium dioxide doped with PVC2, and (D) is an EDS elemental distribution map of titanium dioxide doped with PVC2.

[0038] Figure 3 The mechanical properties and whiteness values ​​of the PVC, PVC-TiO2-1 and PVC-TiO2-2 sheets prepared for Example 3 are shown in the figure. (A) represents Young's modulus, (B) represents tensile strength, (C) represents elongation at break, and (D) represents whiteness value. Detailed Implementation

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0041] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0042] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0043] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0044] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0045] Example 1

[0046] A method for preparing superwetting titanium dioxide based on aggregates:

[0047] (1) The inorganic coated titanium dioxide was provided by Dawn Titanium Industry and was coated with Al2O3 and SiO2; the titanium dioxide was rutile titanium dioxide with a diameter of 200-300 nm.

[0048] The mass of Al2O3 is 3.61% of the mass of inorganically coated titanium dioxide;

[0049] The mass of SiO2 is 1.55% of the mass of the inorganically coated titanium dioxide.

[0050] (2) Sodium polyacrylate (molecular weight of 4000-6000 g / mol) was added to deionized water with pH 7 to obtain a sodium polyacrylate aqueous solution with a concentration of 5 wt%.

[0051] Polyacrylamide (cationic type, molecular weight 5000-8000 g / mol, ionicity 30%) was added to deionized water at pH 7 to obtain a 5 wt% polyacrylamide aqueous solution.

[0052] Inorganic-coated titanium dioxide was added to a 5 wt% sodium polyacrylate aqueous solution and stirred vigorously (500 rpm / min) for 1 h. Then, under stirring conditions (500 rpm / min), a 5 wt% polyacrylamide aqueous solution was added, and stirring was continued for 0.5 h (500 rpm / min) until large viscous agglomerates appeared at the bottom and the supernatant became clear. The supernatant was poured off, and the lower viscous agglomerates were washed twice with water, dried, and pulverized to obtain superwetting titanium dioxide based on agglomerates.

[0053] The total mass of sodium polyacrylate in the sodium polyacrylate solution and polyacrylamide in the polyacrylamide solution is 5% of the mass of the inorganically coated titanium dioxide.

[0054] The mass ratio of sodium polyacrylate in the sodium polyacrylate solution to polyacrylamide in the polyacrylamide solution is 46:54.

[0055] Example 1

[0056] The superwetting titanium dioxide based on aggregates prepared in Example 1 was pressed into a film using a flat vulcanizing machine (pressed at room temperature for 10 minutes under 10 MPa pressure) to obtain a superwetting titanium dioxide film. The contact angles of the superwetting titanium dioxide film with solvents of different polarities (i.e., solvents with different surface tensions) were then tested. The results are shown in Table 1 and... Figure 1 .

[0057] Figure 1 Figure (A) shows the contact angle of water on the surface of the superwetted titanium dioxide film, and Figure (B) shows the contact angle of n-hexane on the surface of the superwetted titanium dioxide film.

[0058] Table 1. Contact angles of superwetting titanium dioxide films to solvents of different polarities (20℃)

[0059]

[0060] from Figure 1 As can be seen, the contact angles of water and n-hexane on the surface of the superwetted titanium dioxide film are both 0°.

[0061] As can be seen from Table 1, the superwetting titanium dioxide film exhibits superwetting properties (contact angle of 0°) in solvents ranging from low surface tension hexane to high surface tension water.

[0062] Example 2

[0063] Comparative titanium dioxide (Dawn Titanium Industry R-3195, which uses the same inorganic coated titanium dioxide as super-wetted titanium dioxide, but uses a small molecule organic coating agent) and PVC (the mass of the comparative titanium dioxide is 3% of the mass of PVC) were mixed, extruded and granulated using a twin-screw extruder (extrusion granulation conditions: 150℃ in zone 1, 170℃ in zone 2, 180℃ in zone 3, 180℃ in zone 1 of the die head, 180℃ in zone 2 of the die head, cylindrical particles 2mm (diameter) × 4mm (column length)) to obtain titanium dioxide doped with PVC1.

[0064] The super-wetting titanium dioxide based on aggregates prepared in Example 1 was mixed with PVC (the mass of the super-wetting titanium dioxide was 3% of the mass of PVC), and then extruded and granulated using a twin-screw extruder (extrusion granulation conditions: zone 1 150°C, zone 2 170°C, zone 3 180°C, die head zone 1 180°C, die head zone 2 180°C, cylindrical particles 2mm (diameter) × 4mm (column length)) to obtain titanium dioxide doped with PVC2.

[0065] The dispersion of titanium dioxide and the aggregate-based superwetting titanium dioxide prepared in Example 1 in PVC substrates was analyzed and compared. The results are shown in the figure. Figure 2 .

[0066] Figure 2 Figure (A) is a cross-sectional SEM image of titanium dioxide doped with PVC1, Figure (B) is an EDS elemental distribution map of titanium dioxide doped with PVC1, Figure (C) is a cross-sectional SEM image of titanium dioxide doped with PVC2, and Figure (D) is an EDS elemental distribution map of titanium dioxide doped with PVC2.

[0067] Figure 2 The green color in diagrams (B) and (D) represents titanium dioxide.

[0068] from Figure 2 As can be seen, incorporating the superwetting titanium dioxide based on aggregates prepared in Example 1 into the PVC substrate can make the titanium dioxide dispersed individually, and the dispersibility is significantly improved compared with the control titanium dioxide.

[0069] Example 3

[0070] PVC substrate, PVC doped with comparative titanium dioxide (i.e., titanium dioxide-doped PVC1), and PVC doped with aggregate-based superwetting titanium dioxide (i.e., titanium dioxide-doped PVC2) were respectively pressed into sheets using a flat vulcanizing machine (pressed at 170℃ for 5 minutes under 10MPa pressure, thickness 3.4mm). The resulting sheets were PVC, PVC-TiO2-1, and PVC-TiO2-2. Tensile properties and whiteness were tested according to ISO 527-2:2019 standard. The results are shown in [Figure number missing]. Figure 3 .

[0071] Figure 3 In the figure, (A) represents Young's modulus, (B) represents tensile strength, (C) represents elongation at break, and (D) represents whiteness value.

[0072] from Figure 3 As can be seen, the Young's modulus, tensile strength, elongation at break, and whiteness of PVC doped with aggregate-based superwetting titanium dioxide (PVC-TiO2-2) are significantly superior to those of PVC doped with comparative titanium dioxide (PVC-TiO2-1). This further demonstrates that the aggregate-based superwetting titanium dioxide prepared in Example 1 has better interfacial wettability and dispersibility with PVC, thus exhibiting significant performance advantages.

[0073] Example 2

[0074] Same as Example 1, except that the 5 wt% polyacrylamide aqueous solution was replaced with a 5 wt% polymethacryloyloxyethyltrimethylammonium chloride solution; thus, superwetting titanium dioxide based on aggregates was prepared.

[0075] The superwetting titanium dioxide based on aggregates prepared in this embodiment was used to prepare a superwetting titanium dioxide film, and the same solvent contact angle test as in Table 1 was performed, and the contact angle was 0° for all films.

[0076] Comparative Example 1

[0077] Same as Example 1, except that the 5 wt% polyacrylamide aqueous solution was replaced with a 5 wt% polyallylamine hydrochloride solution. Precipitation formed; aggregates could not be formed.

[0078] Comparative Example 2

[0079] Same as Example 1, except that the 5 wt% sodium polyacrylate aqueous solution was replaced with a 5 wt% polyvinyl alcohol solution. No aggregates could form.

[0080] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing superwetting titanium dioxide based on aggregates, characterized in that, Includes the following steps: Inorganic coated titanium dioxide is added to sodium polyacrylate solution for a first stirring reaction. Then, polyacrylamide solution or polymethacryloyloxyethyltrimethylammonium chloride solution is added for a second stirring reaction. The aggregate phase is dried and then pulverized to obtain the aggregate-based superwetting titanium dioxide.

2. The preparation method according to claim 1, characterized in that, The inorganic-coated titanium dioxide includes titanium dioxide coated with Al2O3 and SiO2.

3. The preparation method according to claim 2, characterized in that, The mass of Al2O3 is 3-5% of the mass of the inorganically coated titanium dioxide; The mass of SiO2 is 1 to 2.5% of the mass of the inorganically coated titanium dioxide; The diameter of the titanium dioxide is 200-300 nm.

4. The preparation method according to claim 1, characterized in that, The concentration of the sodium polyacrylate solution is 5-10 wt%. The concentration of the polyacrylamide solution is 5-10 wt%. The concentration of the polymethacryloyloxyethyltrimethylammonium chloride solution is 5–10 wt%.

5. The preparation method according to claim 1, characterized in that, When the substance added after the first stirring reaction is a polyacrylamide solution, the total mass of sodium polyacrylate in the sodium polyacrylate solution and polyacrylamide in the polyacrylamide solution is 0.5 to 7% of the mass of the inorganically coated titanium dioxide.

6. The preparation method according to claim 5, characterized in that, The molecular weight of the sodium polyacrylate is 4000-6000 g / mol; The polyacrylamide has a molecular weight of 5000-8000 g / mol and an ionic degree of 20-50%.

7. The preparation method according to claim 5, characterized in that, The mass of the sodium polyacrylate is 20-60% of the total mass of sodium polyacrylate and polyacrylamide.

8. The preparation method according to claim 1, characterized in that, The first stirring reaction takes 0.5 to 1 hour; The second stirring reaction takes 0.5 to 2 hours.

9. A superwetting titanium dioxide based on aggregates prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the aggregate-based superwetting titanium dioxide of claim 9 in the preparation of plastics, fibers, rubber, coatings, inks, paper, cosmetics, separation films or pharmaceuticals.

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