防凍劑,又稱阻凍劑、抗凍劑,是防止液體凝固或組成過大的冰晶的物質。
在汽車上使用時,防凍劑除了要防止它們在高於引擎最低工作溫度的溫度凝固,兼防止冷凍系統的金屬生鏽。1930年代前,甲醇是最流行的防凍劑,可是它的熱容量和沸點都很低,而且時間一長,它的份量都漸漸因蒸發而減少。1937年,開始使用乙二醇,其沸點高,使得它取代甲醇,直到現在仍流行。其缺點是有毒。丙二醇是沒有毒性的防凍劑,它以甘油為原料。1980年代Jack Evans發現使用無水的防凍劑——乙二醇及丙二醇的混合液,其沸點超過攝氏180度。
冬天進行建築工程時常要在混凝土內加入防凍劑,在中國常為尿素和氨水,後果是氨氣會慢慢釋放出來。[1]
二甲基亞碸、丙二醇是常用於生物的防凍劑。
Antifreeze - Wikipedia, the free encyclopedia
en.wikipedia.org/wiki/AntifreezeAn antifreeze is a chemical additive which lowers the freezing point of a water-based liquid. An antifreeze mixture is used to achieve freezing-point depression ... Antifreeze Common Wastes & Materials | US EPA
www.epa.gov/osw/conserve/materials/antifree.htmAntifreeze is a substance added to a solvent, such as water, to lower its freezing point. Antifreeze is typically added to water in the cooling system of an ...Antifreeze | Learn About Chemicals Around Your House | Pesticides ...
www.epa.gov/kidshometour/products/coolant.htmAntifreeze is a bright yellow or green liquid with a slightly sweet smell. It is used in the radiators of cars, trucks and other motor vehicles. Antifreeeze works to ...
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