The main material is a heat-conducting polymer composite.

The main material is a heat-conducting polymer composite.

Text/Polymer

Thermal conductive materials play an indispensable role in various fields of national defense military industry and in development process of civilian economy, and with development of Internet and microelectronics technology, electronic products are developing towards diversified functions, convenient portability and ultra-thin. Aviation, LED energy-saving lamps, civil and military fields are developing towards smaller sizes and higher power, which makes market for thermal conductive materials huge. So, today let's look at heat-conducting polymeric materials.

The main material is a heat-conducting polymer composite.

Figure 1. Fields of application of thermally conductive polymeric materials

1. The concept of thermal conductivity

The so-called thermal conductivity refers to transfer of energy between objects due to movement of microscopic units of movement of atoms, molecules and free electrons. If there is a temperature difference in different areas of material, heat will be transferred from an area with a high temperature to an area with a low temperature until temperature of entire object reaches equilibrium. Table 1-1 - thermal conductivity of a thermally conductive filler.

The main material is a heat-conducting polymer composite.

Table 1-1 Thermal conductivity of common thermally conductive fillers

Although polymer materials have many advantages such as light weight, insulation, ease of processing and molding, most polymer materials are poor conductors and have not been directly applied in some areas of thermal conductivity. There are currently two methods for modifying thermal conductivity of high resolution materials, as shown in Table 1-2.

The main material is a heat-conducting polymer composite.

Table 1-2 Classification of thermally conductive polymer composite materials

Internal thermal conductive polymer materials have high requirements for equipment and process conditions, and industrial production is difficult to implement, filling modification method is to use some high thermal conductivity fillers to fill polymer to make filler uniform Dispersed in high molecular weight polymers and contact with each other, forming a bonded thermal conduction network, thereby improving heat transfer performance of composite material. The most common PA6 thermal conductive composite generally also uses this method.

2. Factors affecting thermal conductivity of thermally conductive polymeric materials

2.1 Polymer matrix

Crystallinity, internal composition and structure of polymer matrix, presence of polar groups in it and degree of dipolarization of polar groups are main factors affecting thermal conductivity of thermally conductive polymer composites.

The main material is a heat-conducting polymer composite.

Table 2-1 Thermal conductivity of common polymeric materials

2.2 Thermally conductive filler

Filling amount: The thermal conductivity of polymeric materials continuously increases with increase in filling amount of thermally conductive fillers. The higher filling amount, higher thermal conductivity of composite material, because heat transfer network in system is gradually improved, and heat transfer accelerates with increase in amount of filling by thermal conductivity.

Filler Shape: Thermally conductive fillers have spherical, fibrous, filamentous, scaly, hexagonal and amorphous shapes, and thermal conductivity, particle size, geometric shape and other factors of filler itself can not only affect their accumulation in resin, but also have a great influence on thermal conductivity of composite material.

The main material is a heat-conducting polymer composite.

Fig. 2. Electrically conductive spherical thermal filler

Modifying interface between base material and filler: Increasing bonding force at interface and interaction between filler and matrix can reduce dissipation of phonon heat at interface and improve thermal conductivity of composite materials.

3. Application of heat-conducting polymer composite materials

Thermal conductive polymer materials, including thermally conductive plastics, thermally conductive rubber, thermally conductive adhesives, etc., have penetrated various fields and are rapidly developing, replacing metal or other thermally conductive materials.

The main material is a heat-conducting polymer composite.

Table 3-1 Applications of thermally conductive polymer composites

4. Conclusion

In short, due to low processing temperature, low density, easy molding, corrosion resistance and good insulation, thermally conductive polymer materials compensate for low corrosion resistance of metal materials, processing complexity, high cost, high transportation costs. , and heavy quality Defects will further increase market demand for thermally conductive polymers.

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