Does nitrile rubber harden at low temperatures?

FOREVER SEALS NBR does harden at low temperatures The following is a detailed explanation of the low temperature hardening of NBR:

1. Causes of hardening

Nitrile rubber is easy to harden at low temperatures, mainly due to the crystallization of molecular chains such as butyl branches. As the temperature decreases, the interaction between molecular chains increases, and chain crystallization becomes the dominant factor. Chain crystallization makes NBR more brittle and hard, which affects its performance.

Second, hardening performance

The hardening of NBR at low temperatures will cause its flexibility and elasticity to decrease significantly, and may even harden and embrittlement, thereby losing its original properties. This hardening phenomenon will affect the use of NBR at low temperatures, especially in cases where elasticity and sealing properties need to be maintained.

3. Influencing factors

Acrylonitrile content: The acrylonitrile content in nitrile rubber has a direct effect on its low temperature performance. The higher the acrylonitrile content, the higher the low temperature brittleness temperature of nitrile rubber, the worse the low temperature resistance.

Glass transition temperature: Glass transition temperature (Tg) is an important indicator to measure the low temperature resistance of rubber. The Tg value of NBR is usually between -20 ° C and -40 ° C, depending on the acrylonitrile content and other formulation factors. The lower the Tg value, the better the low temperature resistance of the rubber.

Prevention and control measures

In order to prevent and control the hardening of nitrile rubber at low temperatures, the following measures can be taken:

Add additives: Add additives such as anti-aging, shock resistance and flexibility to improve the low temperature resistance of nitrile rubber.

Select high-quality raw materials: Control molecular weight distribution and reduce the tendency of chain crystallization, thereby improving the low temperature performance of NBR.

Surface treatment: The surface of nitrile rubber is treated to enhance its surface activity to improve its performance at low temperatures.

Reasonable design: According to the actual needs of the design, combined with the use of the environment and other factors, reasonable material selection and process design.

Nitrile rubber will harden at low temperature, but by taking a series of measures can effectively prevent and control this hardening phenomenon. In practical applications, it is necessary to carry out reasonable material selection and process design to ensure that NBR can play an excellent performance.

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