Application of silicon fiber polymer in adhesive

2024-10-19 09:33:15 Jiangxi dstone 123

Overview of adhesivesAny connecting medium that can closely connect the same or different substances through the surface, can play the role of stress transfer and can meet certain physical and chemical performance requirements can be called adhesive.Adhesive is one of the six polymer materials (including adhesives, coatings, plastics, rubber, fibers and polymer-based composite materials). It is mainly composed of bonding substances, curing agents, toughening agents, diluents, functional polymer materials and modifiers. It is widely used in construction industry, transportation, equipment manufacturing and maintenance, electronics and electrical appliances industry, new energy equipment manufacturing, aviation, aerospace, military industry and medical industry.


Functions and requirements of silicon fiber polymer in adhesivesAdhesive additive is a kind of material that does not react chemically with the main material in the adhesive component, but can change its properties.Additives in the adhesive can not only reduce the cost, but also improve many properties of the adhesive.


1. Improve the mechanical properties of the adhesive and play a reinforcing role.

Some polymers have weak intermolecular interaction and low cohesive energy, so their mechanical properties are not high. Choosing proper particle size filler can play a reinforcing role. The active surface of filler particles can be combined with several macromolecular chains to form a cross-linked structure. When one of the molecular chains is stressed, the stress dispersion can be transferred to other molecules through the cross-linking point. If one of the chains breaks, the other chains can still work without endangering the whole immediately, so the mechanical properties of the adhesive can be greatly improved. Commonly used fillers, such as metal powder and metal oxide, can improve the compressive strength and dimensional stability of the adhesive and reduce the shrinkage. But it will also reduce some properties of the adhesive, such as peel strength. Adding carbon black, white carbon black and calcium carbonate to rubber can improve tensile strength, hardness and wear resistance.


2. Give the adhesive new functions.

Conductive adhesive can be prepared by adding metal powder with good conductivity such as silver powder into glue; Metal powders such as copper powder and aluminum powder are used as fillers to improve the thermal conductivity of the adhesive; When special conductive carbon black, carbon-based iron powder and magnetic powder are added as fillers, the conductive or magnetic adhesive used in special occasions can be prepared. Zinc chromate is added to epoxy resin to improve the strength retention rate; Adding Zr(SO3)2 can reduce the water absorption of epoxy resin. Adding 50% antimony trioxide to the filler can enhance the ability of oxidation resistance. Some fillers can also improve the wet-heat aging resistance and salt spray resistance of bonded joints.


3. Reduce the thermal expansion coefficient and curing shrinkage of the adhesive.

Glue decreases in volume and increases in density during curing, which is caused by chemical action. In addition to the shrinkage caused by the curing process, due to the different thermal expansion coefficients of the adhesive and the adherend, thermal shrinkage will also occur. These two kinds of shrinkage will produce internal stress in the adhesive layer, resulting in stress concentration, which will lead to cracking of the adhesive layer or damage of the joint, which will directly affect the service life of the adhesive joint. The filler can adjust the shrinkage rate in the curing process, reduce the difference of thermal expansion coefficient between the adhesive and the adherend, and prevent the crack from extending, so it can significantly improve the bonding strength, especially the shear strength at high temperature.


4. Increase the viscosity of the glue solution, improve the thixotropy and improve the operation process.

Adding filler can play a thickening role, avoiding glue shortage caused by glue flowing in the curing process, and the thickening effect of fiber filler is obvious. In addition, it can improve the thixotropy of glue to control the fluidity of glue, adjust the curing speed, prolong the service life and be beneficial to operation and construction.


matters need attention

The addition of filler in the adhesive should be appropriate and reasonable, otherwise it will not only improve the performance of the adhesive, but also affect the cohesiveness of the adhesive and play the opposite role. The selection of fillers generally has the following requirements:

① No chemical reaction with other components in the amount of adhesive.

② It is easy to disperse and has good lubricity with the binder.

③ It does not contain moisture, grease and harmful gas, and is not easy to absorb moisture.

④ Non-toxic.

⑤ It has a certain physical state, such as uniform particle size of powdery filler.

⑥ It should meet the special requirements of adhesive, such as electrical conductivity and heat resistance.

⑦ Low cost, wide sources and convenient processing.


There are many kinds of adhesives, and the fillers used for different purposes are also different, and the types and dosage of fillers also have great influence on the properties of adhesives. Non-metallic mineral powder materials commonly used in adhesives mainly include calcium carbonate, talcum powder, graphite, quartz powder, asbestos fiber, mica, titanium dioxide, alumina and so on.

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Let's classify them from the perspective of different roles played by fillers in adhesives:

1. The fillers to improve its impact resistance are asbestos fiber, glass fiber, calcium carbonate, mica powder, aluminum powder, etc.

2. The fillers to improve its hardness and compressive properties are: metal and its oxides, quartz sand, chromium oxide powder, porcelain powder, iron powder, cement, boron carbide, etc.

3. The fillers to improve its wear resistance are graphite powder, talcum powder, calcium carbonate, molybdenum disulfide, etc.

4. The fillers to improve its heat resistance are asbestos powder, silica gel powder, phenolic resin, porcelain powder, titanium dioxide powder, etc.

5. The fillers to increase its adhesion are: alumina powder, porcelain powder, titanium dioxide, etc.

6. The fillers to increase its thermal conductivity are: aluminum powder, copper powder, iron powder, silver powder, carbon black, graphite powder, etc.

7. Fillers to increase its conductivity are: carbon black, graphite, carbon fiber, carbon nanotubes, silver powder, etc.

8. The fillers to increase its lubricity are graphite powder, kaolin, talcum powder and aluminum disulfide;

9. The fillers for increasing magnetic conductivity are: magnetite powder and other magnetic substances.