英语翻译Cross-LinkingIn addition to the bonds which hold monomer

英语翻译
Cross-Linking
In addition to the bonds which hold monomers together in a polymer chain,many polymers form bonds between neighboring chains.These bonds can be formed directly between the neighboring chains,or two chains may bond to a third common molecule.Though not as strong or rigid as the bonds within the chain,these cross-links have an important effect on the polymer.Polymers with a high enough degree of cross-linking have "memory." When the polymer is stretched,the cross-links prevent the individual chains from sliding past each other.The chains may straighten out,but once the stress is removed they return to their original position and the object returns to its original shape.
One example of cross-linking is vulcanization .In vulcanization,a series of cross-links are introduced into an elastomer to give it strength.This technique is commonly used to strengthen rubber.
Classes of Polymers
Polymer science is a broad field that includes many types of materials which incorporate long chain structure of many repeat units as discussed above.The two major polymer classes are described here.
Elastomers,or rubbery materials,have a loose cross-linked structure.This type of chain structure causes elastomers to possess memory.Typically,about 1 in 100 molecules are cross-linked on average.When the average number of cross-links rises to about 1 in 30 the material becomes more rigid and brittle.Natural and synthetic rubbers are both common examples of elastomers.Plastics are polymers which,under appropriate conditions of temperature and pressure,can be molded or shaped (such as blowing to form a film).In contrast to elastomers,plastics have a greater stiffness and lack reversible elasticity.All plastics are polymers but not all polymers are plastics.Cellulose is an example of a polymeric material which must be substantially modified before processing with the usual methods used for plastics.Some plastics,such as nylon and cellulose acetate,are formed into fibers (which are regarded by some as a separate class of polymers in spite of a considerable overlap with plastics).As we shall see in the section on liquid crystals,some of the main chain polymer liquid crystals also are the constituents of important fibers.Every day plastics such as polyethylene and poly(vinyl chloride) have replaced traditional materials like paper and copper for a wide variety of applications.The section on Polymer Applications will go into greater detail about the special properties of the many types of polymers.

交联
除了债券持有单体结合在高分子链,许多聚合物债券形式的邻国间连锁店.这些债券可形成直接往来的周边连锁店,或两个链路,可将保证金第三方共同分子.虽然没那么强烈,或僵化的,因为债券链,这些跨国联系有着重要作用,对聚合物.聚合物具有足够高的程度交联有"记忆" .当聚合物是伸展,两岸三通,防止个别连锁店从滑过去对方.连锁店可以理顺,但一旦需要强调的是拆除他们回到自己原来的立场和客体返回其原来的形状.
其中一个例子交联是硫化.在硫化,一系列的交叉环节引入弹性体给它的实力.这种技术一般是用来加强橡胶.
班聚合物
高分子科学是一个广泛的领域,其中包括许多类型的材料,其中包括长链结构的许多重复单位正如上面所讨论的.两大聚合物班都是形容这里.
弹性体,或胶状物质,有一个松散的交联结构.这种类型的链结构的原因,弹性体拥有的记忆.通常情况下,约1 100个分子交联的平均值.当平均人数两岸三通上升到约1 30物质变得更为刚性和脆性.天然和合成橡胶的,都是常见的例子弹性体.塑料是高分子聚合物,其中,在适当条件下的温度和压力下,可以塑造的,或形（如吹,以形成一个电影）.相比之下,以橡胶,塑料有更大的刚度和可逆缺乏弹性.所有塑料是高分子材料,但并非所有的聚合物塑料.纤维素是一个例子,某高分子材料,其中必须大幅度修改,才会处理与通常采用的方法为塑料.某些塑料,如尼龙和醋酸纤维素,是形成纤维（即却被某些作为一个单独的一类聚合物,虽然有相当多的重叠与塑料）.正如我们应当看到,在关于液晶的,其中一些主链高分子液晶材料,也都是选民的重要纤维.每天塑料,如聚乙烯和聚（氯乙烯）,已经取代传统材料如纸张和铜为各种不同的应用程式.一节聚合物的应用将进入更加详细地了解了特殊性能的多种类型的聚合物.