阅读说明：本技术 聚甲基丙烯酸甲酯/二氧化钛纳米复合材料及其制备方法 (Polymethyl methacrylate/titanium dioxide nano composite material and preparation method thereof ) 是由 张琢 赵鹏 郑义 郑玉丽 高楠 于 2020-06-28 设计创作，主要内容包括：本发明提供一种聚甲基丙烯酸甲酯/二氧化钛纳米复合材料的原位乳液聚合方法。按比例将单体、引发剂、纳米二氧化钛溶胶、乳化剂、溶剂等放入,通过原位乳液法,控制反应温度和时间,反应完成后即可获得聚甲基丙烯酸甲酯/二氧化钛纳米复合材料。本发明的原位乳液制备方法将纳米二氧化钛均匀的分布在聚甲基丙烯酸甲酯薄膜上,解决了纳米二氧化钛易团聚失效的问题,原位乳液法操作简单,反应迅速、可控,反应条件温和,能够实现工业规模生产。制备得到的聚甲基丙烯酸甲酯/二氧化钛复合材料不仅透明性良好,同时还具有较高的抗菌性能,增强了材料的抗紫外性,可广泛应用于光学和卫生领域。(The invention provides an in-situ emulsion polymerization method of a polymethyl methacrylate/titanium dioxide nano composite material. The monomer, the initiator, the nano titanium dioxide sol, the emulsifier, the solvent and the like are put in proportion, the reaction temperature and the reaction time are controlled by an in-situ emulsion method, and the polymethyl methacrylate/titanium dioxide nano composite material can be obtained after the reaction is finished. The in-situ emulsion preparation method of the invention uniformly distributes the nano titanium dioxide on the polymethyl methacrylate film, solves the problem that the nano titanium dioxide is easy to agglomerate and lose efficacy, has simple operation, rapid and controllable reaction and mild reaction conditions, and can realize industrial scale production. The prepared polymethyl methacrylate/titanium dioxide composite material has good transparency, high antibacterial performance and enhanced ultraviolet resistance, and can be widely applied to the fields of optics and sanitation.)

1. The polymethyl methacrylate/titanium dioxide nano composite material is characterized by comprising nano titanium dioxide microspheres combined on a polymethyl methacrylate film, wherein the mass percent of polymethyl methacrylate is 90-99.9%, and the mass percent of titanium dioxide is 0.1-5%.

2. The polymethyl methacrylate/titanium dioxide nanocomposite material according to claim 1, wherein the nano titanium dioxide microspheres have an average particle size of 5 to 20 nm.

3. The preparation method of the polymethyl methacrylate/titanium dioxide nanocomposite material according to claim 1 or 2, characterized by dispersing 0.1-3 parts by mass of modified nano titanium dioxide in a mixed solution of 5-30 parts of an acrylate monomer and 0.15-1 part of an emulsifier, then adding 70-95 parts of deionized water, magnetically stirring and dispersing for 20-60 min, heating to 30-100 ℃, then adding 0.1-0.5 part of an initiator, and preserving heat for 4-8 h to obtain the polymethyl methacrylate/titanium dioxide nanocomposite material.

4. The method for preparing the polymethyl methacrylate/titanium dioxide nanocomposite material as claimed in claim 3, wherein the method for preparing the modified nano titanium dioxide comprises the following steps: according to the mass parts, 10-20 parts of tetrabutyl titanate and a solvent are mixed and then subjected to ultrasonic dispersion, 2-4 parts of deionized water are added, 2-5 parts of hydrochloric acid are added, 0.5-2 parts of silane coupling agent are added, and the obtained system reacts for 2-6 hours to obtain the modified nano titanium dioxide.

5. The method of claim 4, wherein the solvent is methanol, ethanol, isopropanol or acetone.

6. The method for preparing a polymethylmethacrylate/titanium dioxide nanocomposite according to claim 4, wherein the silane coupling agent is γ -aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ -propyltrimethoxysilane or γ -methacryloxypropyltrimethoxysilane; the mass percentage of the silane coupling agent in the system is 0.1-2%.

7. The method for preparing the polymethyl methacrylate/titanium dioxide nanocomposite material according to claim 4, wherein the reaction temperature of the system is 25 to 100 ℃.

8. The method for preparing the polymethyl methacrylate/titanium dioxide nanocomposite material according to claim 3, wherein the acrylate monomer is methyl methacrylate, n-butyl acrylate and acrylic acid in a mass ratio of 1: 1: (0.05-0.5) mixing; the emulsifier is sodium dodecyl sulfate and polyethylene glycol octyl phenyl ether in a mass ratio of 1: (0.1-1) mixing; the initiator is potassium persulfate.

9. The method for preparing the polymethyl methacrylate/titanium dioxide nanocomposite as claimed in claim 3, wherein the amount of the emulsifier added is 0.5 to 3% by mass of the acrylate monomer.

10. The process for preparing a polymethylmethacrylate/titanium dioxide nanocomposite according to claim 3, wherein the modified nano titanium dioxide is added in an amount of not more than 10% of the sum of the masses of all the raw materials.

Technical Field

The invention relates to a method for preparing an in-situ emulsion of a polymethyl methacrylate/titanium dioxide nano composite material, belonging to the technical field of composite materials.

Background

The polyacrylate emulsion not only has the advantages of environmental protection, low cost, good film-forming property and the like, but also has good performances of weather resistance, flexibility, adhesive force and the like of a coating film, but has poor heat resistance, hardness and the like. The inorganic nano titanium dioxide has small size effect, surface interface effect, quantum size effect and macroscopic quantum tunnel effect, and is organically combined with the polyacrylate emulsion to prepare the organic-inorganic nano composite emulsion, so that the properties of the emulsion film such as hardness, heat resistance, impact strength and the like can be obviously improved, and the application range of the emulsion film is further expanded. The titanium dioxide is introduced into the polymer to prepare the inorganic/organic composite material with high refractive index. The composite material has the advantages of organic materials (light weight, flexibility, impact resistance and excellent processability) and inorganic materials (good chemical resistance, high thermal stability and hardness), and the refractive index of the composite material can be easily controlled by adjusting the ratio of inorganic phase to organic phase.

Because of the wide application of polymethyl methacrylate, the preparation method of polymethyl methacrylate nano composite material attracts attention, and the preparation method of suspension polymerization polymethyl methacrylate/titanium dioxide nano composite microsphere (CN101302265B) is beaded powder with the average grain diameter of 40-80 μm; a solvent thermal polymerization method of polymethyl methacrylate/titanium dioxide nano composite material (CN 102604135A); polymethyl methacrylate/silica microspheres prepared by the core/shell method are modified by fluorosilane to form hydrophobic polymethyl methacrylate/silica suspension (CN108101385A) and the like.

The main preparation methods for preparing the polymethyl methacrylate/titanium dioxide nano composite material are a mechanical blending method, a sol-gel method and an in-situ emulsion polymerization method. Although the mechanical blending method has simple process and high production efficiency, the required equipment is conventional equipment, but the prepared composite emulsion nano titanium dioxide has serious agglomeration phenomenon, poor storage stability, easy occurrence of adverse phenomena such as layering, sedimentation and the like. Although the sol-gel method has mild synthesis conditions, the components are easy to control; the prepared nano particles are relatively fine and have good chemical uniformity. However, during the gelling process, the water or solvent is volatilized to some extent, so that the material shrinks and is easy to crack. At present, with the development of emulsion polymerization technology, the preparation method of nano titanium dioxide/acrylate polymer composite emulsion is developed towards an in-situ emulsion polymerization method, and the composite emulsion prepared by the in-situ emulsion polymerization method has better storage stability and good dispersibility of titanium dioxide.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the nano titanium dioxide is easy to agglomerate and lose efficacy, and the dispersibility of the nano titanium dioxide is improved.

In order to solve the technical problem, the invention provides a polymethyl methacrylate/titanium dioxide nano composite material which is characterized by comprising nano titanium dioxide microspheres combined on a polymethyl methacrylate film, wherein the mass percent of polymethyl methacrylate is 90-99.9%, and the mass percent of titanium dioxide is 0.1-5%.

Preferably, the average particle size of the nano titanium dioxide microspheres is 5-20 nm.

The invention also provides a preparation method of the polymethyl methacrylate/titanium dioxide nano composite material, which is characterized by dispersing 0.1-3 parts by mass of modified nano titanium dioxide in a mixed solution of 5-30 parts by mass of an acrylate monomer and 0.15-1 part by mass of an emulsifier, then adding 70-95 parts by mass of deionized water, magnetically stirring and dispersing for 20-60 min, heating to 30-100 ℃, adding 0.1-0.5 part by mass of an initiator, and preserving heat for 4-8 h to obtain the polymethyl methacrylate/titanium dioxide nano composite material.

Preferably, the preparation method of the modified nano titanium dioxide comprises the following steps: according to the mass parts, 10-20 parts of tetrabutyl titanate and a solvent are mixed and then subjected to ultrasonic dispersion, 2-4 parts of deionized water are added, 2-5 parts of hydrochloric acid are added, 0.5-2 parts of silane coupling agent are added, and the obtained system reacts for 2-6 hours to obtain the modified nano titanium dioxide.

More preferably, the solvent is methanol, ethanol, isopropanol or acetone.

More preferably, the silane coupling agent is gamma-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, gamma-propyltrimethoxysilane or gamma-methacryloxypropyltrimethoxysilane; the mass percentage of the silane coupling agent in the system is 0.1-2%.

More preferably, the reaction temperature of the system is 25-100 ℃.

Preferably, the acrylate monomer is methyl methacrylate, n-butyl acrylate and acrylic acid in a mass ratio of 1: 1: (0.05-0.5) mixing; the emulsifier is sodium dodecyl sulfate (anionic emulsifier) and polyethylene glycol octyl phenyl ether (nonionic emulsifier) in a mass ratio of 1: (0.1-1) mixing; the initiator is potassium persulfate.

Preferably, the addition amount of the emulsifier is 0.5-3% of the mass of the acrylate monomer.

Preferably, the adding amount of the modified nano titanium dioxide is not more than 10 percent of the sum of the mass of all raw materials.

The invention improves the stability of the emulsion, has simple method and mild reaction condition and is convenient for large-scale production. The composite emulsion latex particles are nano titanium dioxide, polymethyl methacrylate is used as a matrix to disperse the nano titanium dioxide, the storage stability is good, and the nano titanium dioxide has excellent dispersibility in acrylate polymers.

The reaction mechanism of the invention is an in-situ emulsion polymerization method, which comprises the steps of firstly putting an emulsifier, water, a monomer and organically modified nano particles into a reactor, stirring and jointly dispersing the mixture in micelles, and finally carrying out free radical polymerization on an acrylate monomer under the action of an initiator to generate the organic-inorganic nano composite emulsion in situ. Instead of monomers, acrylate oligomers may also be used in this process. The organic modified nano-particles are used for ensuring good compatibility with acrylate monomers and polymers thereof and avoiding agglomeration.

Compared with the prior art, the invention has the beneficial effects that: the polymethyl methacrylate/titanium dioxide composite material provided by the invention is prepared by an in-situ emulsion polymerization method, and the coating rate of the nano titanium dioxide is high; the prepared polymethyl methacrylate/titanium dioxide composite material can stably enable 10-20 nm titanium dioxide to be attached to a polymer film, so that the antibacterial property of the material is enhanced; and the preparation method is simple and has good industrial prospect.

Drawings

FIG. 1 is an infrared spectrum of a polymethylmethacrylate/titanium dioxide composite material prepared in example 1.

Detailed Description

In order to make the invention more comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings.