To improve the wettability and dispersibility of titanium dioxide reasonably and effectively, organic solutions must be carried out, mainly using surfactants or additives.

The organic improvement of the titanium dioxide surface is to carry out organic coating on the surface of the particles through the chemical reaction or physical absorption of organic molecules on the surface of the particles, transform the surface state of the particles, so that it can be effectively dispersed in the organic solvent, and improve the powder in the organic matter. Compatibility in the interface. Generally can be divided into esterification method, surfactant method, coupling agent method and polymer coating method.

(1) Esterification reaction method

Many hydroxyl groups on the surface of the titanium dioxide particles react with acid to make the acid bond to the surface layer of the particles, which reduces the surface layer of the particles and prevents the hydrogen bonding force of the titanium dioxide particles due to the presence of hydroxyl groups. Li Zongwei et al. modified the titanium dioxide nanoparticles with the surface layer of oleic acid, and successfully generated nanometer titanium dioxide with oil dispersibility.

(2) Coupling agent method

Silane coupling agent is one of the earlier and most widely used coupling agents. It is commonly used to solve fillers with acidic or neutral surface layers such as silica, aluminum oxide, glass fiber, silicate, and clay. It is the coupling agent with the largest number of types and the highest dosage at this stage.

Some easily hydrolyzable groups such as methyl and vinyl in the silane coupling agent can produce some covalent bonds with the hydroxyl group on the surface of titanium dioxide, and then couple the coupling agent to the surface of titanium dioxide. The silane coupling agent needs to choose the appropriate dosage and treatment method to achieve the improvement effect. Actually, it is shown that by absorbing two trimethylsilyl groups on the surface layer of titanium dioxide, the surface layer can be converted into a lipophilic surface layer.

(3) Surfactant method

The adsorption of the surfactant on the surface of the titanium dioxide is not balanced, but it is adsorbed in the active area of the surface. There are many active points and types on the surface of titanium dioxide, but a certain active point can only absorb a certain type of polar groups in a specified form, so it is reasonable and effective to modify the different application functions of titanium dioxide.

(4) Polymer coating method

By coating the polymer on the surface of the titanium dioxide, the van der Waals force between the particles is reduced, and a new type of repulsion-steric hindrance is generated, which is beneficial to its dispersion in the polymer material to improve the titanium dioxide and the polymer matrix Compatibility between. The polymer coating method includes a pretreatment method and an immediate coating method.

The pretreatment method is due to the strong polarity of the surface layer of titanium dioxide, organic monomers and polymers are difficult to absorb on the surface layer, and the solution rate is low. Generally, pretreatment is carried out with coupling agents, surfactants, polymers, etc. first to reduce The surface layer is active, and then polymer coating modification is carried out on the surface of titanium dioxide.

The immediate coating method is based on the existence of free radicals and positive and negative ions on the surface of titanium dioxide, which can cause vitality and can immediately cause monomers to converge on the surface.

At this stage, the surface treatment process has become the most critical key competitiveness in the titanium dioxide field. It can be predicted that in the very long period of time now and in the future, the competition in the titanium dioxide field will be manifested to a very large extent by the titanium dioxide surface treatment process. Competition, therefore, enhancing the discussion and promotion of key technology and practical application of titanium dioxide surface treatment will play a key role in enhancing the overall development level of my country's titanium dioxide field and enhancing international competitiveness.