TWI716185B - Method for stably dispersing nsp in water - Google Patents

Abstract

In the present invention, nanoscale silicate platelets (NSPs) are mixed with an organic gelling agent in water to form a NSP/organic compound. The NSP/organic compound can stably disperse in water in a weight ratio of 50/1 to 1/1. Optionally, a surfactant is added to enhance dispersibility of NSPs in water by forming a NSP/surfactant/organic compound.

Description

Method for stably dispersing nano silicon wafers in water

The present invention relates to a method for stably dispersing nano-silicon flakes in water, in particular to a method for stably dispersing nano-silicon flakes in water by adding a gel or thickening agent to react with the nano-silicon flakes to form a complex.

Nanoscale silicate platelets (NSP) are delamination silicate clays with geometric appearance and high sheet-to-diameter ratio of about 100×100×1nm3~300×300×1nm3. The cation exchange capacity is about 1.2 mequiv/g and the surface area About 500m2/g. Because NSP has a high surface area and charge, it has a tendency to accumulate and precipitate in water, thereby reducing its surface activity. In addition, it is difficult for the NSP dispersion to maintain its uniformity, which is not conducive to practical applications.

Gelling agent (or thickener, gelling agent or thickener) is a substance that can increase the viscosity of a liquid without changing its characteristics. Many natural gels have been used in medical, food and other fields. The selection of a proper gelling agent can prevent the self-aggregation of specific substances in water at the proper pH, thus improving its dispersibility.

Therefore, the present invention attempts to add different proportions of gelling agents to NSP of different concentrations to improve the dispersibility of NSP. In addition, it is matched with various interface active agents to achieve the best dispersion effect.

The main purpose of the present invention is to provide a method for stably dispersing nano-silicon wafers in water. To this end, the present invention also provides a nano-silicon wafer composite with good dispersion in water.

The method for stably dispersing nano-silicon wafers in water of the present invention includes the following steps:

(A) Prepare a gelling agent aqueous solution with a concentration of 0.5wt%-20wt%, and a nanosilicon flake (NSP) aqueous solution with a concentration of 0.1wt%-10wt%, wherein the gelling agent is a water-soluble organic compound. The silicon wafers are completely delaminated silicic acid clay with a diameter ratio of 100×100×1nm ³ ~300×300×1nm ^3. The nano silicon wafer solution is stirred at 50℃~99℃ for 0.2~1 hour;

(B) Add the gelling agent solution to the NSP solution, the solid content of NSP/gelling agent is 0.1wt%~10wt%, and the weight ratio of NSP/gelling agent is 50/1~1/1; and

(C) Stir at 20-80°C for 0.5-5 hours to make the gelling agent and NSP react in water to form an NSP/gelling agent complex, which is uniformly and stably dispersed in water.

In the above method, the gel may be sodium alginate, methyl cellulose, agar, polysaccharides from algae or kelp, cellulose acetate, chitosan, glucosamine, acetyl glucosamine, hyaluronic acid , Glucuronic acid, corn sugar gum, Guanhua soybean gum, modified food starch, corn flour, sweet potato starch, water-soluble starch, high fructose syrup, mung bean starch, wheat starch, polydextrose, soy flour, cyclodextrin, Maltodextrin, carboxymethyl cellulose, cellulose, gum arabic, carrageenan, xanthan gum, alginic acid or polyethylene glycol. The weight ratio of the NSP/gelling agent is preferably 20/1 to 5/1.

Between the above steps (A) and (B), there may be another step:

(A’) Prepare an aqueous solution of an interfacial surfactant with a concentration of 1% to 20% by weight. The interfacial surfactant is a water-soluble nonionic surfactant or an anionic surfactant, and the interfacial surfactant is added to the NSP aqueous solution. Surfactant solution, make the weight ratio of NSP/surfactant be 99/1~20/80, and stir at 50℃~99℃ for 0.2~2 hours to form NSP/surfactant compound;

Therefore, the NSP solution in step (B) is changed to an NSP/surfactant complex solution, and the NSP/gelling agent complex in step (C) is changed to an NSP/surfactant/gelling agent complex.

The aforementioned nonionic surfactant is preferably a polyoxyethylene compound, more preferably a polyoxyethylene sorbitan fatty acid ester or a polyoxyethylene alkyl ether. The anionic surfactant is preferably sodium dodecyl sulfonate. The weight ratio of NSP/interface active agent is preferably 95/5~20/80, more preferably 90/10~30/70.

The above-mentioned nanosilicon flake composite can be stably and uniformly dispersed in water to form a dispersion, which further includes step (D), the dispersion obtained in step (C) is freeze-dried, hot-air drying or vacuum spraying methods Dry and store in powder form. The nanosilica composite in powder form can be mixed with water to prepare dispersions of various concentrations for convenient use.

The method of the present invention therefore provides a composite of nano-silicon wafers, which is an NSP/gel-agent composite formed by a nano-silicon wafer (NSP) and a gel. The gel, the nanosilicon wafer, and the NSP/gel complex are as described above.

The composite of the aforementioned nanosilicon wafer may further include a water-soluble surfactant to form an NSP/surfactant/gel complex. The interface active agent is also as described above.

Figure 1 shows the dispersion of NSP complex in water after adding sodium alginate.

Figure 2 shows the dispersion of NSP complex in water after adding sodium alginate and non-ionic surfactant SINOPOL 1830.

Figure 3 shows the dispersion of NSP complex in water after adding sodium alginate and non-ionic surfactant TWEEN ^® 60.

Figure 4 shows the dispersion of NSP complex in water after adding sodium alginate and two non-ionic surfactants, SINOPOL 1830/TWEEN ^® 60.

Figure 5 shows the dispersion of NSP complex in water after adding sodium alginate and cationic surfactant Ablumine 1214.

Figure 6 shows the dispersion of NSP complex in water after adding sodium alginate and an anionic surfactant, sodium dodecyl sulfonate.

The materials used in the preferred embodiments and comparative examples of the present invention include:

1. Natural gelling agent or thickening agent: Sodium alginate is used in the examples, but others are methylcellulose, agar, polysaccharides from algae or kelp, and cellulose acetate Cellulose acetate, chitosan, glucosamine, acetyl-glucosamine, hyaluronic acid, glucuronic acid, xanthan gum ), guar gum, modified food starch, corn flour, sweet potato starch, water-soluble starch, high fructose syrup, mung bean starch, wheat starch, polydextrose, soy flour, cyclodextrin, malt paste Refined, carboxymethyl cellulose, cellulose, gum arabic, carrageenan, xanthan gum, alginic acid or polyethylene glycol are also suitable.

2. Nonionic surfactants: fatty alcohol ethoxylates or polyoxyethylene alkyl compounds, such as:

(a) TWEEN ^® series: It is a kind of polyoxyethylene sorbitan fatty acid ester, the general chemical formula is RO-(CH ₂ CH ₂ O) _x -H, R is alkyl or alcohol group, x>15, more Preferably it is 10-100, or Hydrophilic Lipophilic Balance (HLB)>12. In the example, TWEEN ^® 60 (polyoxyethylene sorbitan monostearate, HLB=14.9) is selected, others such as TWEEN ^® 80 (polyoxyethylene sorbitan monooleate, HLB=15), TWEEN ^® 85 (polyoxyethylene sorbitan trioleate, HLB=11) and TWEEN ^® 20 (polyoxyethylene sorbitan) monolaurate, HLB=16.7) also applies.

(b) SINOPOL 1800 series: purchased from China-Japan Synthetic Chemical Company, it is a polyoxyethylene alkyl ether, the general chemical formula is RO-(CH ₂ CH ₂ O) _x -H, R is an alkyl group, x>16, Preferably it is 10-100, or HLB>12. The embodiment uses SINOPOL 1816 (Polyoxyethylene Alkyl(C ₁₈ )Ether, HLB=14), others such as SINOPOL 1825 (Polyoxyethylene Alkyl(C ₁₈ )Ether, HLB=16) and SINOPOL 1830 (Polyoxyethylene Alkyl(C ₁₈ )Ether, HLB= 16) Also applicable.

3. Cationic surfactant: Ablumine 1214 (Alkyl dimethyl benzyl ammonium chloride, alkyl dimethyl aniline hydrochloride) is selected in the examples, which is a C12~C18 tallow amine hydrochloride or hydrogenated tallow Amine hydrochloride. Purchased from Taiwan surfactant Co.

4. Anionic surfactant: Sodium dodecyl sulfonate (SDS) is used in the examples.

5. Montmorillonite (Na+-MMT): purchased from Nanocor Ind. Co., the cation exchange capacity is about 1.2 mequiv/g.

6. Nano silicon wafer (NSP): Refer to US Patent No. 7,022,299B2, No. 7,094,815B2, No. 7,125,916B2, and Announcement No. 2005-0239943-A1, and Application No. 11/464,495. be made of. The following is one of the methods, including the following steps:

(a) Disperse montmorillonite (10g) in hot water (1L) at 80°C and stir vigorously for 4 hours to make the aqueous solution form a stable and uniform dispersion of earthy color.

(b) Take p-cresol (27.2g) and D2000 (757.6g) at a molar ratio of 2:3, reflux in toluene at 90°C for 3 hours, then add formaldehyde solution (37wt%, 61.4g), and heat to React at 130°C for 5 hours, and stop the reaction after forming a gel. The resulting product is Amine-termination Mannich Oligomer (AMO). GPC analysis showed that the three peak positions were Mw=3,142, 6,221 and 9,246 respectively; the amine titration results were: primary amine=0.4meq/g, secondary amine=0.56meq/g, no tertiary amine. AMO was dissolved in water (575g) and mixed with concentrated hydrochloric acid (35wt%, 36g) at 80°C for 30 minutes to form acidified AMO. Pour the acidified AMO into the above-mentioned Na ⁺ -MMT dispersion and stir vigorously at 80° C. for 5 hours to complete the intercalation reaction and obtain an AMO/Clay mixed solution.

(c) Add buffer aqueous solutions of different pH values to the AMO/Clay mixed solution. At this time, the AMO/Clay mixed solution will form a light yellow, emulsified viscous liquid.

(d) Add ethanol (7.5L) to the viscous liquid and filter it, then add ethanol (10L) to the filtered solid and stir evenly and add the equivalent of NaOH (9.2g) and filter it to obtain a light yellow, translucent AMO/NSP103S flake silicate mixture, the organic/inorganic ratio (organic/inorganic, O/I) of this mixture is about 40/60.

(e) Add the above-mentioned AMO/NSP mixture to ethanol (10L) and stir evenly and equivalent NaOH, then add water (10L) and stir evenly, finally add toluene (10L) and mix well. After standing for one day, it is divided into three layers, the top layer is toluene and AMO (recyclable), the middle layer is ethanol, and the bottom layer is the desired product NSP suspension.

Example 1 Preparation of NSP/Sodium Alginate Complex

Proceed as follows:

(A) Prepare an aqueous solution of sodium alginate with a concentration of 3wt% and an aqueous solution of NSP with a concentration of 3wt%. The NSP aqueous solution must be mechanically stirred at 80°C for 0.5 hours.

(B) Add different volumes of sodium alginate solution to 4 bottles of NSP solution so that the weight ratio of NSP/sodium alginate is (a) 100/0, (b) 20/1, (c) 10/1 , (D) 5/1.

(C) Mechanically stir the NSP/sodium alginate complex solution, react at 20-80°C for 0.5 hours, and observe its dispersion.

(D) Dry the NSP/sodium alginate complex solution to obtain a white fine powder.

Example 2~3 Preparation of NSP/Sodium Alginate Complex

Repeat the steps (A) to (D) of Example 1, but the concentration of the NSP aqueous solution was changed to 1wt% and 0.5wt%.

Figure 1 shows the dispersion of the NSP/sodium alginate complex solution in Examples 1 to 3. The dispersion of NSP with high initial concentration is obviously better when the concentration is lower, and the dispersion of NSP is also better when the content of sodium alginate is higher.

Example 4 Preparation of NSP/SINOPOL 1830/sodium alginate complex

Proceed as follows:

(A) Prepare an aqueous solution of sodium alginate with a concentration of 3wt% and an aqueous solution of NSP with a concentration of 3wt%. The NSP aqueous solution must be mechanically stirred at 80°C for 0.5 hours.

(A') Prepare an aqueous solution of SINOPOL 1830 with a concentration of 10 wt%. Add the SINOPOL 1830 solution to the NSP aqueous solution so that the weight ratio of NSP/SINOPOL 1830 is 9/1, and stir at 80°C for 1 hour.

(B) Add different volumes of sodium alginate solution to 4 bottles of NSP/SINOPOL 1830 solution so that the weight ratio of NSP/sodium alginate is (a) 100/0, (b) 20/1, (c) 10 /1, (d) 5/1.

(C) Mechanically stir the NSP/SINOPOL 1830/sodium alginate complex solution, react at 20-80°C for 0.5 hours, and observe its dispersion.

(D) The NSP/SINOPOL 1830/sodium alginate complex solution was spray-dried in vacuum at 200°C to obtain a white fine powder.

Example 5~6 Preparation of NSP/SINOPOL 1830/sodium alginate complex

Repeat the steps (A) to (D) of Example 4, but the concentration of the NSP aqueous solution was changed to 1wt% and 0.5wt%.

Figure 2 shows the dispersion of the NSP/SINOPOL 1830/sodium alginate complex in water in Examples 4-6. Compared with Examples 1 to 3, the addition of SINOPOL 1830 does help to evenly disperse NSP in water. Similarly, the higher the sodium alginate content, the better the dispersibility of NSP.

Examples 7~9 Preparation of NSP/TWEEN® 60/sodium alginate complex

Repeat Examples 4-6, but replace SINOPOL 1830 with TWEEN® 60.

Figure 3 shows the dispersion of NSP/TWEEN® 60/sodium alginate complex. Compared with Examples 1~3, the addition of TWEEN® 60 also helps to disperse NSP uniformly in water. In some examples, TWEEN® 60 is better than SINOPOL 1830. Similarly, the higher the sodium alginate content, the better the dispersibility of NSP.

Examples 10~12 Preparation of NSP/SINOPOL 1830/TWEEN® 60/sodium alginate complex

Repeat Examples 4~6, but add two surfactants SINOPOL 1830 and TWEEN® 60 at the same time.

Figure 4 shows the dispersion of NSP/SINOPOL 1830/TWEEN® 60/sodium alginate complex. Compared with Examples 4-9, the effect of adding two interface active agents is not as good as adding only a single one. For example, (11a) has obvious sediment on the bottom of the bottle, while (5a) has a little sediment, and (8a) has none. But the higher the sodium alginate content, the better the dispersibility of NSP.

Examples 13~15 Preparation of NSP/Ablumine 1214/sodium alginate complex

Repeat Examples 4-6, but replace SINOPOL 1830 with the cationic surfactant Ablumine 1214.

Figure 5 shows the dispersion of the NSP/Ablumine 1214/sodium alginate complex. In the figure, there are obvious aggregation of NSP particles on the wall of each test bottle. Although the addition of sodium alginate helps to the dispersion effect of NSP, cationic surfactants are not as beneficial as nonionic surfactants.

Examples 16~18 Preparation of NSP/Sodium Dodecyl Sulfonate/Sodium Alginate Complex

Repeat Examples 4-6, but replace SINOPOL 1830 with sodium dodecyl sulfonate, an anionic surfactant.

Figure 6 shows the dispersion of the NSP/sodium dodecyl sulfonate/sodium alginate complex. Although there are NSP particles gathered at the bottom of some test bottles, the dispersion is obviously better than that of Ablumine 1214. And adding sodium alginate can significantly improve the dispersion effect of NSP.

The above-mentioned nano-silicon flake composite can be stably and uniformly dispersed in water to form a dispersion; it can also be dried by freeze drying, hot air drying or vacuum spraying, and stored in the form of powder. The nanosilica composite in powder form can be mixed with water to prepare dispersions of various concentrations for convenient use.

Table 1 shows the dispersion effect in water of the above Examples 1-18, with different weight ratios of NSP/sodium alginate and the addition of different surfactants.

(a)(b)(c)(d)：NSP/藻酸鈉重量比 ○：均勻穩定分散液；△：底部有些許沉積；×：底部有大量沉積

(a)(b)(c)(d): NSP/sodium alginate weight ratio ○: uniform and stable dispersion; △: a little deposit on the bottom; ×: a lot of deposit on the bottom

As shown in Table 1, the present invention can improve the dispersibility of NSP by adding different proportions of gelling agent to NSP of different concentrations. In addition, it is matched with various interface active agents to achieve the best dispersion effect.

Claims (9)

A method for stably dispersing nano-silicon flakes in water includes the following steps: (A) preparing a gelling agent aqueous solution with a concentration of 0.5 wt% to 20 wt%, and a nano-silicon flake (NSP) with a concentration of 0.1 wt% to 10 wt% ) An aqueous solution, wherein the gelling agent is a water-soluble organic compound, selected from sodium alginate, methylcellulose, agar, polysaccharides from algae or kelp, cellulose acetate, chitosan, glucosamine, ethyl acetate Glucosamine, hyaluronic acid, glucuronic acid, corn sugar gum, Guanhua bean gum, modified food starch, corn flour, sweet potato starch, water-soluble starch, high fructose syrup, mung bean starch, wheat starch, polydextrose, soybean flour , Cyclodextrin, maltodextrin, carboxymethyl cellulose, cellulose, gum arabic, carrageenan, xanthan gum, alginic acid and polyethylene glycol group, the nano silicon wafer is The completely delaminated silicic acid clay, the sheet diameter ratio is 100×100×1nm ³ ~300×300×1nm ³ , the nano-silicon wafer aqueous solution is stirred at 50℃~99℃ for 0.2~1 hour; (B) The glue aqueous solution is added to the NSP aqueous solution, the solid content of NSP/gelling agent is 0.1wt%~10wt%, the weight ratio is 20/1~5/1; and (C) Stirring 0.5~5 at 20~80℃ After hours, the gelling agent and NSP will form an NSP/gelling agent complex in water and be uniformly and stably dispersed in water. The method according to claim 1, wherein between step (A) and step (B) there is a further step: (A') preparing an aqueous solution of an interface active agent with a concentration of 0.5 wt% to 20 wt%, and the interface active agent is Water-soluble non-ionic surfactant or anionic surfactant, add the surfactant solution to the NSP aqueous solution so that the weight ratio of NSP/interface surfactant is 99/1~20/80, and the temperature is 50℃~99℃ Stir for 0.5~2 hours to form an NSP/surfactant complex; therefore, the NSP aqueous solution in step (B) is changed to NSP/surfactant complex solution, and the NSP/gelling agent complex in step (C) is changed to NSP /Interface active agent/Gel Agent complex. The method according to claim 2, wherein the nonionic surfactant is a fatty alcohol polyoxyethylene ether or a polyoxyethylene alkyl compound. The method according to claim 3, wherein the non-ionic surfactant is polyoxyethylene sorbitan fatty acid ester or polyoxyethylene alkyl ether. The method according to claim 2, wherein the anionic surfactant is sodium dodecyl sulfonate. The method according to claim 2, wherein the NSP/interface active agent weight ratio is 95/5 to 20/80. The method according to claim 1, which further comprises step (D): drying the dispersion formed in step (C) into a powder form. A nano-silicon flake composite comprising nano-silicon flakes (NSP) and a gel, wherein the gel is a water-soluble organic compound selected from sodium alginate, methyl cellulose, agar, and algae Or polysaccharides of kelp, cellulose acetate, chitosan, glucosamine, acetyl glucosamine, hyaluronic acid, glucuronic acid, corn sugar gum, Guanhua bean gum, modified food starch, corn flour, sweet potato starch, Water-soluble starch, high fructose syrup, mung bean starch, wheat starch, polydextrose, soy flour, cyclodextrin, maltodextrin, carboxymethyl cellulose, cellulose, gum arabic, carrageenan, xanthan gum , Alginic acid and polyethylene glycol group, the nano-silicon wafer is a completely delaminated silicic acid clay, the wafer diameter ratio is 100×100×1nm ³ ~ 300×300×1nm ³ , the nano-silicon wafer It forms an NSP/gelling agent composite with the gelling agent, the solid content of the NSP/gelling agent is 0.1wt%-10wt%, and the weight ratio is 20/1-5/1. The nanosilicon wafer composite as described in claim 8 further includes an interfacing agent to form an NSP/interfacing agent/gelling agent complex. The interfacing agent is a water-soluble nonionic surfactant or an anionic interface Active agent, the weight ratio of NSP/interface surface active agent is 99/1~20/80.

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