合成橡胶的特性(Properties of synthetic rubber)
氯丁橡胶,是由氯丁二烯(即2-氯-1,3-丁二烯)为主要原料进行α-聚合而生产的合成橡胶,被广泛应用于抗风化产品、粘胶鞋底、涂料和火箭燃料。
外观为乳白色、米黄色或浅棕色的片状或块状物,是氯丁二烯(即2-氯-1,3-丁二烯)为主要原料进行α-聚合生成的弹性体。氯丁橡胶溶解度参数占δ=9.2~9.41。溶于甲苯、二甲苯、二氯乙烷、三钒乙烯,微溶于丙酮、甲乙酮、醋酸乙酯、环己烷,不溶于正己烷、溶剂汽油,但可溶于由适当比例的良溶剂和不良溶剂及非溶剂或不良溶剂和非溶剂组成的混合溶剂,在植物油和矿物油中溶胀而不溶解。
有良好的物理机械性能,耐油,耐热,耐燃,耐日光,耐臭氧,耐酸碱,耐化学试剂。缺点是耐寒性和贮存稳定性较差。具有较高的拉伸强度、伸长率和可逆的结晶性,粘接性好。耐老化、耐热。耐油、耐化学腐蚀性优异。耐候性和耐臭氧老化仅次于乙丙橡胶和丁基橡胶。耐热性与丁腈橡胶相当,分解温度230~260℃,短期可耐120~150℃,在80~100℃可长期使用,具有一定的阻燃性。耐油性仅次于丁腈橡胶。耐无机酸、碱腐蚀性良好。耐寒性稍差,电绝缘性不佳。生胶储存稳定性差,会产生“自硫”现象,门尼黏度增大,生胶变硬。
Neoprene is a synthetic rubber produced by α-polymerization of chloroprene (i.e. 2-chloro-1,3-butadiene) as the main raw material, and is widely used in weather-resistant products, viscose soles, coatings and rocket fuel.
It is milky white, beige or light brown in appearance as flakes or lumps, and is an elastomer produced by the α-polymerization of chloroprene (i.e. 2-chloro-1,3-butadiene) as the main raw material.The solubility parameters of neoprene accounted for δ=9.2~9.41.It is soluble in toluene, xylene, dichloroethane, trivanadium ethylene, slightly soluble in acetone, methyl ethyl ketone, ethyl acetate, cyclohexane, insoluble in n-hexane, solvent gasoline, but soluble in an appropriate proportion of benign solvent and bad solvent and non-solvent or a mixed solvent composed of a bad solvent and non-solvent, swelling in vegetable oil and mineral oil without dissolution.
It has good physical and mechanical properties, oil resistance, heat resistance, flame resistance, sunlight resistance, ozone resistance, acid and alkali resistance, chemical reagent resistance.Its disadvantages are poor cold resistance and storage stability.It has high tensile strength, elongation and reversible crystallinity with good adhesion. It has excellent aging resistance, heat resistance, oil resistance and chemical resistance. Its weather resistance and ozone aging resistance are second only to ethylene propylene rubber and butyl rubber.Its heat resistance is comparable to nitrile rubber, the decomposition temperature is 230~260 °C, the short-term resistance is 120~150 °C, and it can be used for a long time at 80~100 °C, and has certain flame retardancy.Its oil resistance is second only to nitrile rubber. Its resistance to inorganic acids and alkalis is good, but its cold resistance is slightly poor, and its electrical insulation is not good. Its raw rubber storage stability is poor, which will produce the phenomenon of "self-sulfur", Mooney viscosity increases, and the raw rubber becomes hard.