What are the thermal conductivity parameters of commonly used rubber?

Rubber is divided into natural rubber and synthetic rubber according to raw materials.

Natural rubber NR

Made from latex collected from rubber trees, it is a polymer of isoprene. It has very good wear resistance, high elasticity, tear strength and elongation. It is easy to age in the air, becomes viscous when heated, and in mineral oil.

or gasoline is easy to swell and dissolve, alkali resistant but not resistant to strong acids.

Advantages: good elasticity, acid and alkali resistance. Disadvantages: not weather-resistant, not oil-resistant (vegetable oil resistant) It is a raw material for making tapes, hoses, and rubber shoes, and is suitable for making shock-absorbing parts, brake fluid and ethanol in automobiles.

and other products used in liquids with hydroxide.

Styrene-butadiene gum. Butadiene.

Compared with natural rubber, the copolymer with styrene has uniform quality, less foreign matter, better wear resistance and aging resistance, but weak mechanical strength, and can be mixed with natural rubber. Advantages: low-cost non-oil-resistant material, good water resistance, good elasticity below 70 hardness, poor compressibility at high hardness, disadvantages:

It is not recommended to use strong acids, ozone, oils, oil esters and fats and most hydrocarbons. It is widely used in tire industry, shoe industry, cloth industry and conveyor belt industry.

The name of the material. Density g c m3

Specific heat capacity j (kg.)Rubber: 1700 joules (kg*C) thermal conductivity w (m.)℃)

Natural rubber vulcanized rubber.

Natural rubber hard rubber.

Styrene-butadiene rubber. Neoprene.

Neoprene vulcanized rubber.

Butyl glue. Nitrile rubber. Silastic.

Rubber is divided into natural rubber, including natural rubber vulcanized rubber and natural rubber hard rubber, of course, rubber and synthetic rubber.

Thermal conductivity of synthetic rubber.

As follows: styrene-butadiene rubber.

Neoprene. Neoprene vulcanized rubber.

Butyl oak high scatter mu rubber.

Silastic. Among them, natural rubber is the raw material for making tapes, hoses, and rubber shoes, and is suitable for making shock-absorbing parts, brake fluids and ethanol in automobiles.

and other products used in liquids with hydroxide. Synthetic rubber is widely used in the tire industry, footwear industry, cloth industry and conveyor belt digging and industry.

Thermal conductivity of silicone rubber:. There are also the following classifications::

Natural rubber vulcanized rubber.

Natural rubber hard rubber.

Styrene-butadiene rubber.

Neoprene.

Neoprene vulcanized rubber.

The thermal conductivity of silicone rubber is not important, just know that it conducts almost no heat. However, after the silicone rubber is mixed with ceramic particles with high thermal conductivity, a series of thermally conductive silicone grease with a thermal conductivity of 7 is produced.

Different materials, types of rubber, its thermal conductivity is not the same, the following is the range of thermal conductivity of several types of rubber: natural rubber vulcanized rubber: natural rubber hard rubber: and so on. And the thermal conductivity of the rubber disc:

Thermal conductivity. Thermal conductivity is one of the most important thermal and humid physical parameters of building materials, which is closely related to building energy consumption, indoor environment and many other thermal and humidity processes.

The thermal conductivity is only for the heat transfer form where heat conductivity is present, and when there are other forms of heat transfer, such as radiation, convection, and mass transfer, the composite heat transfer relationship is present.

The thermal conductivity is for homogeneous materials, and in practice, there are porous, multi-layered, multi-structured, and anisotropic materials.

The thermal conductivity of plastics is small, about 1 500-1 600 of metals. The thermal conductivity of foam plastic is only about 1 1500 for metal, 1 40 for cement concrete, and 1 20 for ordinary clay bricks, which is an ideal thermal insulation material.

The relationship between heat transfer coefficient and thermal conductivity can be expressed by the formula: thermal conductivity = thermal conductivity x density x heat capacity.

1. From this formula, it can be seen that the relationship between the thermal conductivity and the conductivity coefficient of the hot slag is very close. The greater the thermal conductivity, the greater the ability of the substance to conduct heat under the temperature gradient, and the greater the thermal conductivity. Conversely, the smaller the thermal conductivity, the smaller the thermal conductivity.

2. Heat transfer coefficient:

In the past, many were referred to as the total heat transfer coefficient. Later, for example, the state unified the name of heat transfer coefficient for the current standards and specifications. The heat transfer coefficient is expressed by k value is a proportion coefficient in the heat transfer process equation, which refers to the heat transferred by 1 square meter area within 1 hour when the air temperature difference on both sides of the enclosure structure is 1 degree (k, ) under stable heat transfer conditions, and the unit is watt square meter degree (w · k, where k can be replaced).

3. Thermal conductivity:

Thermal conductivity refers to the heat transferred by 1 square meter area within 1 hour of a 1 m thick material with a temperature difference of 1 degree (k, ) under stable heat transfer conditions, and the unit is watt m · degree (w m·k, where k can be substituted). The thermal conductivity is related to the composition of the material, density, moisture content, temperature and other factors. Amorphous structure, low density materials, low thermal conductivity.

The conversion relationship between the heat transfer coefficient and the thermal conductivity is as follows:

1. Heat supply refers to the process of heat exchange between the fluid when it flows through a solid wall with a different average temperature from the fluid. Although the heat supply problem involves a solid wall, it is still a convective heat transfer problem from the fluid aspect. By Fourier's Law :

q = into * grad t, the heat flux is proportional to the temperature gradient. The thermal conductivity (thermal conductivity) is included as the scale coefficient in w (m*oc).

2. Newton's law of cooling: dq = a * da (t-tw), the unit of heat supply a is w (m2 * oc), which is different from the thermal conductivity. Therefore, the heat transfer coefficient and the thermal conductivity are different concepts, and in a broad sense, they can be called the heat transfer coefficient.

The thermal conductivity is measured by the thickness of 1 meter, the thermal resistance is proportional to the thickness of the material and inversely proportional to the heat transfer coefficient, and the thermal coefficient of the conductive branch should be divided by the wall thickness [m] to obtain the heat transfer coefficient.