1. Mechanical properties

Fluorine rubber has excellent physical and mechanical properties. Type 26 fluororubber generally has a strength between 10 and 20MPa, an elongation at break between 150 and 350%, and a tear strength between 3 and 4KN/m. Type 23 fluororubber has a strength of 15.0~25MPa, an elongation rate of 200%~600%, and a tear strength of 2~7MPa.

In general, the compression set of fluororubber at high temperature is large, but if compared under the same conditions, such as the compression set at the same time at 150 ° C, both butadiene and neoprene rubber are larger than 26-type fluoroelastomer. The compression deformation of 26-type fluororubber at 200℃×24 hours is equivalent to the compression deformation of butadiene rubber at 150℃×24 hours.

The physical and mechanical properties of silicone rubber at room temperature are worse than that of general-purpose rubber, but at a high temperature of 150 °C and a low temperature of -50 °C, its physical and mechanical properties are better than general-purpose rubber.

2. Low temperature performance

The glass transition temperature of silicone rubber is generally -70~-50℃, and the special formula can reach -100℃, indicating its excellent low temperature performance.

The low temperature performance of fluororubber is not good, which is due to its own chemical structure, such as Tg>0℃ of type 23-11. The low temperature performance of fluororubber actually used is usually expressed by the brittleness temperature and the compression cold resistance coefficient. The formula of the rubber compound and the shape of the product (such as thickness) have a great influence on the brittleness temperature. If the amount of filler in the formula increases, the brittleness temperature is sensitively deteriorated, and the thickness of the product increases, and the brittleness mixing degree is also sensitively deteriorated.

3. Breathability

The air permeability of silicone rubber to air, nitrogen, oxygen, carbon dioxide and other gases at room temperature is 30-50 times higher than that of natural rubber.

The solubility of fluororubber to gas is relatively large, but the diffusion rate is relatively small, so the overall air permeability is also small. According to reports, the air permeability of 26-type fluororubber to oxygen, nitrogen, helium, and carbon dioxide gas at 30 °C is comparable to that of butyl rubber and butadiene rubber, and is better than that of neoprene and natural rubber.