高弹性聚合物。橡胶来自印度词cau uchu,这意味着“泪水树”。天然橡胶由胶乳制成,当切割时从橡胶树中流出,凝固和干燥。橡胶的分子链可以交联。当交联橡胶通过外力变形时,它具有快速恢复,良好的物理和机械性能和化学稳定性的能力。橡胶是橡胶工业的基本原料,广泛用于轮胎,软管,胶带,电缆等橡胶制品。
根据原料,橡胶类型分为天然橡胶和合成橡胶。根据该形状,可分为嵌段橡胶,胶乳,液体橡胶和粉末橡胶。乳胶是橡胶的胶体水分散体;液体橡胶是橡胶的低聚物,其在硫化前通常粘稠;粉末橡胶是乳胶加工成粉末,以便于成分和加工。20世纪60年代开发的热塑性橡胶由热塑性塑料的加工方法形成,无化学硫化。根据使用橡胶分为一般和特殊两种类型。
通用橡胶具有良好的综合性能,广泛使用。有:①天然橡胶。从HEVEA Trifoliata的乳胶,基本化学成分是顺式聚异戊二烯。弹性良好,强度高,综合性能。②异戊二烯橡胶。其全名是CIS-1,4-聚异戊二烯橡胶。由异戊二烯制成的高CIS合成橡胶也称为合成天然橡胶,因为其结构和性质与天然橡胶的结构类似。③苯乙烯丁二烯橡胶。SBR通过丁二烯和苯乙烯的共聚制备。将其分为乳液聚合苯乙烯丁二烯橡胶和溶液聚合的苯乙烯丁二烯橡胶根据生产方法。 Its comprehensive properties and chemical stability are good. ④ Cis-1,4-polybutadiene rubber. The full name is cis-1,4-polybutadiene rubber, abbreviated as BR, which is prepared by polymerization of butadiene. Compared with other general-purpose rubbers, the vulcanized cis-1,4-polybutadiene rubber has excellent cold resistance, wear resistance and elasticity, less heat under dynamic load and good aging resistance. It is easy to be used with natural rubber, chloroprene rubber, nitrile rubber, etc.
特殊橡胶是指带有一些特殊物质的橡胶。主要有:1。氯丁烯橡胶。CR通过氯丁二烯的聚合制备。它具有良好的综合性能,耐油性,耐火性,抗氧化性和耐臭氧性。但其密度大,在室温下易于结晶和硬化,其储存和耐寒性差。②丁腈橡胶。NBR通过丁二烯和丙烯腈的共聚合制备。它可以在120℃或油状物的空气中长时间在150℃下使用。此外,它还具有耐水性,气密性和优异的粘接性能。③硅橡胶。 The main chain is alternately composed of silicon and oxygen atoms with organic groups on the silicon atoms. High and low temperature resistance, ozone resistance, good electrical insulation. ④ Fluororubber. A synthetic rubber containing fluorine atoms in its molecular structure. It is usually expressed by the number of fluorine atoms of fluorine-containing units in the copolymer. For example, fluororubber 23 is a copolymer of vinylidene fluoride and chlorotrifluoroethylene. Fluororubber is resistant to high temperature, oil and chemical corrosion. ⑤ Polysulfide rubber. It is formed by polycondensation of dihaloalkane and alkali metal or alkaline earth metal polysulfide. It has excellent oil resistance and solvent resistance, but its strength is not high, aging resistance and processability are not good, and it has bad smell. It is often used together with NBR. In addition, there are polyurethane rubber, chlorohydrin rubber, acrylate rubber, etc.
橡胶加工的基本过程包括塑化,混合,压延或挤出,模塑和硫化。每个过程对产品有不同的要求,并与多个辅助操作相匹配。为了将各种必需的配合剂加入橡胶,未加工的橡胶需要塑化以提高其可塑性;然后,将炭黑和各种橡胶添加剂与橡胶混合以形成化合物;将橡胶挤出成一定的空白;然后将其在压延后与纺织材料(或金属材料)相结合,并粘合形成半成品;最后,在硫化后,具有可塑性的半成品,具有高弹性的最终产品。
以前的:橡胶垫圈的作用是什么?