Coupling agent: "molecular bridge" between different materials
In the field of materials science and engineering, coupling agent, as a special chemical substance,
plays a vital role. It is like a matchmaker with skillful hands, cleverly promoting the
combination of different materials, thereby enhancing the overall performance of the material.
1. Definition and working principle of coupling agent
As the name suggests, coupling agent is an auxiliary agent with a "coupling" effect. Its molecular
structure is unique and usually consists of two parts: one part is an inorganic-friendly group
that can react chemically with inorganic fillers or reinforcing materials; the other part is an organic-friendly
group that can react chemically with synthetic resins or other polymers or generatehydrogen bonds and dissolve in them.
This dual affinity enables coupling agents to become a link between
inorganic and organic materials, significantly reducing the surface tension between them and promoting mixing
and adhesion.
2. The main advantages of coupling agents
Improving interfacial adhesion: Coupling agents can significantly enhance the adhesion between different
materials and reduce the possibility of their separation. This enhancement allows
composite materials to more effectively transmit stress when subjected to external forces, thereby improving
overall strength.
Improve compatibility: Coupling agents help mix different materials and
make them more compatible. This not
only reduces possible phase separation or cracking, but also improves the
uniformity and stability of the material.
Enhance material properties: Through coupling, coupling agents can significantly improve the physical,
mechanical and chemical properties of materials. For example, it can improve the
strength, stiffness, heat resistance and chemical corrosion resistance of materials, thereby broadening the
application range of materials.
3. Types and applications of coupling agents
There are many types of coupling agents, which are mainly divided into organic chromium complexes,
silane coupling agents, titanate coupling agents and aluminate coupling agents
according to their chemical structure and composition. Among them, silane coupling agents and titanate
coupling agents are the most widely used.
Silane coupling agent: Silane coupling agent is one of the coupling agents with the largest variety,
largest dosage and best effect.
It is widely used in the fields of glass fiber reinforced plastics,
surface treatment of inorganic fillers, sealants, resin concrete, etc. Silane coupling agents can improve
the bonding properties of glass fiber and resin, and greatly improve the strength, water
resistance and weather resistance of composite materials.
Titanate coupling agent: Titanate coupling agent is relatively cheap, and in some cases, it can produce a
synergistic effect when used with silane coupling agent, further improving the coupling
effect. It is suitable for a variety of resin-based composite materials systems, especially for aqueous polymer systems.
Titanate coupling agent is also widely used in the rubber industry, which
can improve the wear resistance and aging resistance of products such as tires and rubber sheets.
In addition, aluminate coupling agent, bimetallic coupling agent, etc. also have their own unique advantages and
application fields. For example, aluminate coupling agent performs well in
improving the physical properties of products, while bimetallic coupling agent has the advantages of low processing
temperature, fast coupling reaction speed, and good dispersibility.
4. Application examples of coupling agents in various fields
Plastic industry: Coupling agent is used to improve the compatibility of plastic resin and filler, thereby improving
the mechanical properties of plastic products. For example, adding coupling
agent to polyolefin resin can improve the compatibility of filler and resin, and improve mechanical properties,
especially impact resistance and elongation.
Coating and ink manufacturing: Coupling agents can reduce the viscosity of coatings, improve the dispersion of
pigments, increase adhesion, and improve coating performance. This makes
coatings and inks more uniform and durable.
Composite materials: Coupling agents are widely used in glass fiber, carbon fiber and wood plastic
composites to improve their performance. In glass fiber reinforced plastics, coupling agents
can significantly improve the strength and weather resistance of composite materials.
Magnetic materials: Coupling agents improve the dispersion and adhesion of magnetic materials in polymers,
thereby improving the performance of magnetic materials.
Adhesive and coating industry: Coupling agents can improve adhesion and weather resistance in wet state,
improve pigment dispersion, improve wear resistance and cross-linking degree of
resin.
5. Conclusion
As a key additive in materials science and engineering, coupling agents significantly improve the adhesion and
compatibility between different materials through their unique molecular
structure and dual affinity, thereby enhancing the overall performance of materials. Whether in the fields of plastics,
coatings, rubber or composite materials, coupling agents play an
indispensable role. With the advancement and innovation of science and technology, the application scope of coupling agents
will continue to expand, contributing more to the development
of materials science.
