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For non-crystalline rubber glass transition temperature is a measure of its cold resistance to temperature indicators. For crystalline rubber, it often reaches the maximum crystallisation rate at temperatures much higher than Tg and crystallises very quickly. Therefore, the cold resistance of crystalline rubber should try to inhibit its crystallisation at low temperatures. Industry often use the brittleness temperature as a product cold resistance performance indicators.
(1) the choice of rubber species rubber main chain containing double bonds and ether bonds (such as NR, BR, chlorohydrin rubber) rubber with high cold resistance. The main chain contains double bonds and has a polar side group of rubber (NBR, CR) cold resistance in the middle. Rubber that does not contain double bonds in the main chain but has polar groups in the side chains (e.g., fluoroelastomer) has the lowest cold resistance. General use of rubber at low temperatures, in addition to low-temperature performance, but also requires other properties, so only the selection of cold-resistant rubber often can not meet the actual requirements, can be used in conjunction with the rubber, so that after the use of the rubber cold resistance can be improved.
(2) vulcanisation system of cold-resistant rubber vulcanisation system, with high sulfur and low promotion of sulfur yellow vulcanisation system is good for non-crystalline rubber, lower crosslinking density of cold-resistant favourable. When low-temperature crystallisation becomes the main contradiction affecting the cold resistance, the crosslink density should be increased to reduce the crystallisation effect.
(3) softening and plasticising system to choose a reasonable softening and plasticising system is to improve the cold resistance of rubber products effective measures. Adding plasticisers can make Tg significantly lower. Cold resistance of poor polar rubber such as nitrile, neoprene, etc. is mainly through the addition of appropriate plasticiser to improve its low temperature performance. For NBR, the most commonly used plasticisers are DOP and DBP. better plasticisers for neoprene are butyl oleate, dioctyl sebacate, with the dosage of 20~30 parts. Non-polar rubber such as NR, BR, SBR can use petroleum hydrocarbons as softeners, can also choose ester plasticisers.
(4) The addition of fillers generally makes the cold resistance of rubber worse, and should be used sparingly or not. If it must be used, soft or spherical fillers should be preferred.
(1) the choice of rubber species rubber main chain containing double bonds and ether bonds (such as NR, BR, chlorohydrin rubber) rubber with high cold resistance. The main chain contains double bonds and has a polar side group of rubber (NBR, CR) cold resistance in the middle. Rubber that does not contain double bonds in the main chain but has polar groups in the side chains (e.g., fluoroelastomer) has the lowest cold resistance. General use of rubber at low temperatures, in addition to low-temperature performance, but also requires other properties, so only the selection of cold-resistant rubber often can not meet the actual requirements, can be used in conjunction with the rubber, so that after the use of the rubber cold resistance can be improved.
(2) vulcanisation system of cold-resistant rubber vulcanisation system, with high sulfur and low promotion of sulfur yellow vulcanisation system is good for non-crystalline rubber, lower crosslinking density of cold-resistant favourable. When low-temperature crystallisation becomes the main contradiction affecting the cold resistance, the crosslink density should be increased to reduce the crystallisation effect.
(3) softening and plasticising system to choose a reasonable softening and plasticising system is to improve the cold resistance of rubber products effective measures. Adding plasticisers can make Tg significantly lower. Cold resistance of poor polar rubber such as nitrile, neoprene, etc. is mainly through the addition of appropriate plasticiser to improve its low temperature performance. For NBR, the most commonly used plasticisers are DOP and DBP. better plasticisers for neoprene are butyl oleate, dioctyl sebacate, with the dosage of 20~30 parts. Non-polar rubber such as NR, BR, SBR can use petroleum hydrocarbons as softeners, can also choose ester plasticisers.
(4) The addition of fillers generally makes the cold resistance of rubber worse, and should be used sparingly or not. If it must be used, soft or spherical fillers should be preferred.
