Titanate coupling agents first appeared in the 1970s. In December 1974, Kenrich Petrochemical Company of the United States reported a new type of coupling agent, which has good coupling effects on many dry powders. Since then, inorganic-filled polyolefin composites with titanate coupling agents have been introduced. In recent years, a series of titanate coupling agents developed by the American company Kenrich have been widely used. Carbon black, SiO2, CaCO3, and metal oxides activated with titanate coupling agents are added to thermoplastics and rubbers to reduce system viscosity and improve toughness and mechanical properties. At present, titanate coupling agent has become one of the indispensable raw materials for composite materials.
Function of titanate coupling agent
1. Structure of titanate coupling agent
Titanate coupling agents can be divided into 4 categories according to their chemical structures: monoalkoxy type, monoalkyl pyrophosphate type, chelate type and ligand type. The molecular formula of titanate coupling agent is: (RO)m Ti (OX-R-Y)n. Its molecular structure determines that it has multiple functions, and its functions are respectively for:
①(RO)m: The R group reacts with the hydroxyl group on the surface of the inorganic filler to form a monomolecular layer of coupling agent, thereby performing chemical coupling. The water and free protons (H+) on the filler interface are reaction points that interact with the coupling agent.
② (O┈): Various types of ester group conversion reactions can occur, which can cross-link titanate coupling agents with polymers and fillers, and can also occur with hydroxyl groups in epoxy resins Esterification reaction.
③X: It is the atomic group connected to the titanium-oxygen bond, or the adhesive group, which determines the characteristics of the titanate coupling agent. These groups include alkoxy, carboxyl, sulfonyloxy, phosphoryloxy, phosphorous acidoxy, pyrophosphoryloxy, etc.
④R: It is the long-chain part of the titanate coupling agent molecule. It mainly ensures the entanglement and miscibility with the polymer molecules, improves the impact strength of the material, reduces the surface energy of the filler, and increases the viscosity of the system. Significantly reduced, and has good lubricity and rheological properties.
⑤Y: It is the functional group used for cross-linking by titanate coupling agent, including unsaturated double bond groups, amino groups, hydroxyl groups, etc.
⑥n: reflects the number of functional groups contained in the titanate coupling agent molecule, which can be 1 to 3.
2. Structure determines application
① In filled plastics, fillers can be activated to increase the filling amount, reduce the amount of resin, reduce product costs, improve processing performance, increase product gloss, and improve quality.
② In rubber, the modified filler can play a reinforcing role, reduce the amount of rubber and antioxidant, improve the wear resistance and anti-aging ability of the product, and improve the surface gloss of the product.
③ It can increase the amount of pigments and fillers added to the paint and improve the dispersion performance; it has an anti-sedimentation effect and can prevent the color from blooming; it can increase the strength of the paint film and make it brighter in color. In addition, it has drying properties, which reduces the baking temperature and shortens the baking time.
④ When used in the coating industry, it can improve the corrosion resistance of coatings and prevent gelation of coatings.
⑤ When used in the papermaking industry, it can improve the dispersion of calcium carbonate or talc powder, greatly reduce loss and loss, and significantly improve the printing performance of paper.
⑥Improve the gel-forming properties, heat-resistant temperature and downhole permeability of fracturing fluid, and significantly increase oil recovery.
⑦ Significantly improve the dispersion of magnetic powder, enhance its affinity with the carrier, increase the filling amount, increase the magnetic density, and improve the magnetic signal.
⑧ Used in adhesives to enhance bonding strength, etc.
Summary
In short, due to the special structure of titanium, it has many unique functions. Countries around the world are actively carrying out research on the application of titanium. Titanium is the fourth most abundant metal element in the earth’s crust. my country has abundant reserves. Therefore, the development and application of organic titanium compounds is the current international development direction. Its application scope Its broad scope and remarkable effect are of great significance to the development of my country’s chemical industry, as well as improving product quality, reducing costs, and improving efficiency.
References
[1] Zhao Zhen, Zhang Wenlong, Chen Yu. Research progress and application of coupling agents [J]. Plastic additives.
[2]Guo Yunliang, Zhang Shurong, Li Liping. Types, characteristics and applications of coupling agents [J]. Rubber Industry.
[3]Li Hongling, Dong Bin, Han Yanan, Lou Shufang, Li Jie, Li Wenjing. Coupling mechanism and research progress of titanate coupling agents [J]. Surface technology.
Source: Powder Circle
