CN103318945A - Preparation method of colloidal solution of nano-ZnO - Google Patents

Abstract

The invention discloses a preparation method of a nanometer zinc oxide colloidal solution. Mix the modified cellulose aqueous solution with a concentration of 0.001-100g/L and the zinc salt solution with a concentration of 0.01-100g/L at a volume ratio of 1:10-100:1, and the modified cellulose is p-hydroxypropyl The dialdehyde hydroxypropyl methylcellulose obtained by selective oxidation of the secondary hydroxyl groups on the C ₂ and C ₃ positions of methyl cellulose; then slowly add alkaline solution dropwise to adjust the pH value to 8.5-11.5, at 20°C Stirring for 1-600 minutes at a temperature of ~90°C until the reaction is complete, that is, a nano-zinc oxide colloidal solution with an average particle size of 1-100 nm is obtained. The prepared nano-zinc oxide has ultra-high stability, antibacterial and ultraviolet resistance, and has good biocompatibility and biodegradability, and can be applied to the fields of coating, textile, medical and health, and the like.

Description

A kind of preparation method of nano zinc oxide colloidal solution

technical field

The invention belongs to the technical field of preparation of nanometer materials, and in particular relates to a preparation method of nanometer zinc oxide colloidal solution.

Background technique

Nano-zinc oxide is a new type of multifunctional inorganic semiconductor material, and its particle size is generally between 1 and 100nm. When the particle size of zinc oxide reaches the nanometer level, special surface effects, volume effects, and quantum size effects will be produced, thereby exhibiting special properties. For example, compared with ordinary zinc oxide, nano-zinc oxide has excellent non-migration, fluorescence, adsorption and scattering of ultraviolet rays, etc., and can be widely used in the fields of electricity, optics, magnetism, and chemical catalysis. Utilizing the absorption performance of nano-zinc oxide on ultraviolet light, ultraviolet detectors, LEDs, LDs and anti-ultraviolet textiles can be prepared. Utilizing the photocatalytic effect of nano-silver zinc oxide, it can be used for treating organic wastewater and antibacterial finishing of textiles. Utilizing the good piezoelectric properties of zinc oxide, it can be used to prepare piezoelectric devices such as acousto-optic modulators. In recent years, some people have also used nano-zinc oxide to develop solar cells, nano-miniature generators, etc. These all show that nano-zinc oxide has very excellent properties and broad application prospects.

Like the preparation methods of many nanomaterials, the preparation methods of nano-zinc oxide are also divided into physical methods and chemical methods. Physical methods include magnetron sputtering, ball milling, pulsed laser deposition, etc. The nano-zinc oxide prepared by the above methods has a smaller particle size and particle size distribution, but requires higher equipment. In addition, for some special requirements of nano-zinc oxide, such as nano-zinc oxide with core-shell structure, nano-zinc oxide with special morphology (nanowire, rod), co-doped nano-zinc oxide, etc., physical methods are often powerless. Chemical methods include co-precipitation method, hydrothermal reaction method, sol-gel method, electrochemical method, etc. The above-mentioned preparation method has low equipment requirements and can realize the specialization of nano-zinc oxide, but the chemical method often has problems such as difficult to control particle size, large size dispersion, and easy agglomeration, which puts higher requirements on the chemical method. the

Nano-silver zinc oxide is widely used in the field of functionalized textiles because of its excellent UV absorption and antibacterial properties. The treatment process of nano-zinc oxide textiles is usually obtained by finishing textiles with nano-zinc oxide colloid solution. The application of nano-zinc oxide in the field of functionalized textiles must meet the following requirements: the particle size of nano-zinc oxide must be uniform and the solution stability is high; the protective agent used to disperse and protect nano-zinc oxide must be safe and non-toxic to the human body, and must comply with Specifications of textiles on surface residues (textiles have strict regulations on the content of surfactants, so surfactants are not suitable as protective agents); nano-zinc oxide protected by protective agents must have good bonding ability with fabrics and have good Durability and washability. Apparently there are very few nano zinc oxides that meet the above requirements.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a nano-zinc oxide colloidal solution with high safety and high solution stability.

In order to better solve the above-mentioned technical problems, the technical solution of the present invention provides a method for preparing a nano-zinc oxide colloidal solution, comprising the steps of:

(1) Mix the modified cellulose aqueous solution with a concentration of 0.001g/L-100g/L and the zinc salt solution with a concentration of 0.01-100g/L at a volume ratio of 1:10-100:1 to obtain a mixed solution; The modified cellulose is dialdehyde hydroxypropyl methylcellulose obtained by selective oxidation of the secondary hydroxyl groups at the _C2 and _C3 positions of hydroxypropylmethylcellulose;

(2) Slowly add the alkaline solution into the mixed solution, control the pH value to 8.5-11.5, and stir for 1-600min at a temperature of 20°C-90°C to obtain nano-oxidized particles with an average particle size of 1-100nm Zinc colloid solution.

The molecular weight of the hydroxypropyl methylcellulose described in the present invention is 1,000-100,000. The zinc salt aqueous solution is one of Zn(NO ₃ ) ₂ , ZnCl ₂ , ZnSO ₄ or Zn(CH ₃ COO) ₂ aqueous solutions. The alkaline solution is an aqueous solution of NH ₃ , NaOH, KOH, and NH ₂ .

For the preparation method of dialdehyde-based hydroxypropyl methylcellulose in the present invention, please refer to the literature "Aggregate Structure of Selectively Oxidized Cotton Fiber" (Xu Yunhui, Lin Hong, Chen Yuyue. [J]. Textile Journal, 2006, 27(11 ): 1-5).

Compared with prior art, the advantage of the present invention is:

1. Hydroxypropyl methylcellulose can be dissolved in aqueous solution to form a high-viscosity aqueous solution, so it has poor protective performance against zinc oxide. The present invention uses sodium periodate to selectively oxidize the secondary hydroxyl groups on the C ₂ and C ₃ positions of hydroxypropyl methylcellulose to obtain a large number of aldehyde groups, resulting in The water solubility is greatly enhanced and the viscosity is greatly reduced; at the same time, the aldehyde group has a highly active conjugated electron cloud, which can effectively limit the growth of zinc oxide crystals and effectively bind to the surface of zinc oxide crystals to achieve the purpose of protection and dispersion.

2. Aiming at the field of textiles, the present invention uses modified cellulose with good safety, biocompatibility and biodegradability to design and prepare a highly stable and safe nano-zinc oxide colloidal solution for human body. Dialdehyde hydroxypropyl methylcellulose has good biocompatibility and biodegradability, and its safety can be fully guaranteed.

3. The prepared nano-zinc oxide colloidal solution has low cost, simple process, good stability, uniform nano-silver particle size, and good anti-ultraviolet and antibacterial effects, and can be widely used in coatings, textiles, medical care and other fields .

Description of drawings

Fig. 1 is the infrared spectrogram of the hydroxypropyl methylcellulose before and after modification provided by the present invention;

Fig. 2 is the prepared nanometer zinc oxide Zeta potential diagram that the embodiment of the present invention provides;

Fig. 3 is the XRD spectrogram of the nanometer zinc oxide that the embodiment of the present invention provides;

Fig. 4 is a SEM image of nano-zinc oxide provided by an embodiment of the present invention.

Detailed ways

The content of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Example 1:

1. Prepare dialdehyde hydroxypropyl cellulose according to the technical scheme provided in the literature "Selectively Oxidized Cotton Fiber Aggregate Structure". The preparation method is: first dissolve hydroxypropyl methylcellulose in deionized water to obtain the mass The percentage is 1% hydroxypropyl methylcellulose solution, and then the mass fraction of 1% sodium periodate aqueous solution is gradually dropped into the above solution, and the volume ratio of the two is 1:1 to 50:1. The reaction temperature was set at 50°C, and the reaction was fully stirred by mechanical stirring in a light-proof environment. After 30 minutes of reaction, the reaction solution was cooled to room temperature. Then, the above solution was dialyzed for 24 hours by using a dialysis bag with a dialysis molecular weight of 5000 to obtain pure dialdehyde hydroxypropyl methylcellulose. Referring to accompanying drawing 1, it is the infrared spectrogram of the hydroxypropyl methylcellulose before and after modification provided by the present embodiment, among the figure, curve a is hydroxypropyl methylcellulose, and curve b is dialdehyde hydroxyl Propyl methyl cellulose; Fig. 1 result shows, hydroxypropyl methyl cellulose appears the characteristic absorption peak of aldehyde group at ^1737cm after sodium periodate oxidation, shows that this reaction can successfully prepare dialdehyde group hydroxypropyl base methyl cellulose. In this example, 0.10 g of dialdehyde hydroxypropyl methylcellulose was dissolved in 100 mL of deionized water to obtain an aqueous solution of dialdehyde hydroxypropyl methylcellulose with a concentration of 1 g/L;

2. Dissolve 0.727g of zinc nitrate in 100mL of deionized water to obtain a zinc nitrate solution with a concentration of 7.27g/L;

3. Dissolve 5.00g of sodium hydroxide in 100mL of deionized water to obtain a sodium hydroxide aqueous solution with a concentration of 50g/L;

4. Mix 1g/L dialdehyde hydroxypropyl methylcellulose aqueous solution and 7.87g/L zinc nitrate aqueous solution at a volume ratio of 4:1, and add 50g/L hydrogen dropwise under constant stirring at 70°C The aqueous solution of sodium oxide (mass ratio of zinc nitrate to sodium hydroxide is 189:80), after 2 hours of reaction, a nano-zinc oxide colloidal solution with a particle size of 10-60nm can be obtained.

Referring to accompanying drawing 2, it is the Zeta potential figure of the nano-zinc oxide colloidal solution that the present embodiment provides; Zeta potential is the important index that characterizes the colloid dispersion system stability. The absolute value of Zeta potential reflects its stability, the larger the absolute value, the better the stability. In general, an absolute value of Zeta potential exceeding 30 mV indicates a high stability of the sample. It can be seen from the figure that the surface Zeta potential of the prepared nano-zinc oxide is -58.6mV (the pH of the zinc oxide colloidal solution is 9.0), such a high surface potential shows that the prepared nano-zinc oxide colloidal solution has high stability. This surface potential is apparently the result of the modification of the surface of nano-zinc oxide with dialdehyde hydroxypropyl methylcellulose, which leads to a large number of hydroxyl and aldehyde groups on its surface. These groups can not only greatly increase the potential of the surface of nano-zinc oxide, but also play the role of effective charge steric hindrance.

Referring to accompanying drawing 3, it is the XRD spectrogram of the nano-silver solution provided by the present embodiment; As can be seen from the figure, compared with the standard card JCPDS No.89-0511, its XRD diffraction peak corresponds completely to the zinc oxide XRD standard spectrogram, 9 The three diffraction peaks correspond to the diffraction peaks of (100), (002), (101), (102), (110), (103), (112), (200) and (201) crystal planes of ZnO, respectively.

Referring to accompanying drawing 4, it is the SEM picture of the nano-silver particles provided by this embodiment, and the magnification is 60,000 times. It can be seen from the figure that the nano-zinc oxide is a standard spherical shape, the particle size is 10-60nm, and the particle size distribution is relatively uniform.

Example 2:

1. Prepare dialdehyde hydroxypropyl methylcellulose according to the technical scheme of embodiment 1. Dissolve 0.20 g of dialdehyde hydroxypropyl methylcellulose in 100 mL of deionized water to obtain an aqueous solution of dialdehyde hydroxypropyl methylcellulose with a concentration of 2 g/L;

2. Dissolve 0.727g of zinc nitrate in 100mL of deionized water to obtain a zinc nitrate solution with a concentration of 7.27g/L;

3. Dissolve 5g of sodium hydroxide in 100mL of deionized water to obtain an aqueous solution of sodium hydroxide with a concentration of 50g/L;

4. Mix 2g/L dialdehyde hydroxypropyl methylcellulose aqueous solution and zinc nitrate aqueous solution with a mass fraction of 7.87g/L at a volume ratio of 4:1, and add 50g/L solution dropwise under constant stirring at 70°C. L of sodium hydroxide aqueous solution (mass ratio of zinc nitrate to sodium hydroxide is 189:80), react for 2 hours to obtain a nano-zinc oxide colloidal solution with a particle size of 10-60nm.

Example 3:

1. Dissolve 0.20 g of dialdehyde hydroxypropyl methylcellulose in 100 mL of deionized water to obtain a dialdehyde hydroxypropyl methylcellulose aqueous solution with a concentration of 2 g/L;

2. Dissolve 0.727g of zinc nitrate in 100mL of deionized water to obtain a zinc nitrate solution with a concentration of 7.27g/L;

3. Dissolve 5mL of ammonia water in 95mL of deionized water to obtain an aqueous ammonia solution;

4. Mix 2g/L dialdehyde hydroxypropyl methylcellulose aqueous solution and zinc nitrate aqueous solution with a mass fraction of 7.87g/L at a volume ratio of 4:1, and add ammonia aqueous solution dropwise under constant stirring at 70°C (The mass ratio of zinc nitrate to ammonia water is 189:20). After 2 hours of reaction, a nano-zinc oxide colloidal solution with a particle size of 10-60nm can be obtained.

Claims (4)

1. the preparation method of a nano zine oxide colloidal solution is characterized in that comprising the steps:

(1) is that the modified-cellulose aqueous solution and the concentration of 0.001g/L～100g/L is that the zinc salt solution of 0.01～100g/L mixes with the volume ratio of 1:10～100:1 with concentration, obtains mixing solutions; Described modified-cellulose is to Vltra tears C ₂, C ₃Secondary hydroxyl on the position carries out the dialdehyde-based Vltra tears that selective oxidation obtains;

(2) basic solution slowly is added drop-wise in the mixing solutions, control pH value is 8.5～11.5, then stirs 1～600min under 20 ℃～90 ℃ temperature condition, and namely obtaining median size is the nano zine oxide colloidal solution of 1～100nm.

2. the preparation method of a kind of nano zine oxide colloidal solution according to claim 1, it is characterized in that: it is 1000～100000 that described Vltra tears molecular weight should be.

3. the preparation method of a kind of nano zine oxide colloidal solution according to claim 1, it is characterized in that: described zinc salt solution is Zn (NO ₃) ₂, ZnCl ₂, ZnSO ₄Or Zn (CH ₃COO) ₂The aqueous solution in a kind of.

4. the preparation method of a kind of nano zine oxide colloidal solution according to claim 1, it is characterized in that: described basic solution is NH ₃, NaOH, KOH, NH ₂The aqueous solution.

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