21、compounds are able to form chain-0like macromolecules through elimination of the double bond, a phenomenon first recognized by Staudinger. Diolefins polymerize in the same manner, however, only one of the two double bonds is eliminated. Such reactions occur through the initial addition of a monomer。

22、molecule to an initiator radical or an initiator ion, by which the active state is transferred from the initiator to the added monomer. In the same way by means of a chain reaction ，one monomer molecule after the other is added （200020000 monomers per second） until the active state is terminated thr 。

【完整|(完整word版)高分子材料工程专业英语翻译】23、ough a different type of reaction 。
The polymerization is a chain reaction in two ways: because of the reaction kinetic and because as a reaction product one obtains a chain molecule. The length of the chain molecule is proportional to the kinetic chain length.Staudinger第一个发现一例现象 ， 许多烯烃和不饱和烯烃通过打开双键可以形成 。

24、链式大分子.二烯烃以同样的方式聚合 ， 然而 ， 仅限于两个双键中的一个.这类反应是通过单体分子首先加成到引发剂自由基或引发剂离子上而进行的 ， 靠这些反应活性中心由引发剂转移到被加成的单体上 。
以同样的方式,借助于链式反应,单体分子一个接一个地被加成（每秒200020000个单体）直到活性中心通过不同的反应类型而终止 。
聚合反应是链式反应的原因有两种：因为反应动力学和因为作为反应产物它是一种链式分子 。
链分子的长度与动力学链长成正比.One can summarize the process as follow （R. is equal to the initiator radical）:链式反应可以概括为以 。

25、下过程（R相当与引发剂自由基）：略One thus obtains polyvinylchloride from vinylchloride ，or polystyrene from styrene, or polyethylene from ethylene ，etc.因而通过上述过程由氯乙烯得到聚氯乙烯,或由苯乙烯获得聚苯乙烯 ， 或乙烯获得聚乙烯,等等 。
The length of the chain molecules ，measured by means of the degree of polymerization ，can be varied over a large range th 。

26、rough selection of suitable reaction conditions 。
Usually ，with commercially prepared and utilized polymers ，the degree of polymerization lies in the range of 1000 to 5000, but in many cases it can be below 500 and over 10000 。
This should not be interpreted to mean that all molecules of a certain pol 。

27、ymeric material consist of 500 ，or 1000 ，or 5000 monomer units. In almost all cases ，the polymeric material consists of a mixture of polymer molecules of different degrees of polymerization.借助于聚合度估算的分子链长 ， 在一个大范围内可以通过选择适宜的反应条件被改变.通常 ， 通过大量地制备和利用聚合物 ， 聚合度在10005000范围内 ， 但在许多情况下可低于500、高于10000 。
这不应该把所有聚合物材料的分子量理 。

28、解为由500 ， 或1000 ， 或5000个单体单元组成 。
在几乎所有的事例中 ， 聚合物材料由不同聚合度的聚合物分子的混合物组成 。
Polymerization ，a chain reaction ，occurs according to the same mechanism as the wellknown chlorinehydrogen reaction and the decomposition of phosegene 。
聚合反应 ， 链式反应,依照与众所周知的氯(气）-氢（气)反应和光气的分解机理进行 。
The initiation reaction, which is the activation。

29、process of the double bond ，can be brought about by heating ，irradiation ，ultrasonics ，or initiators. The initiation of the chain reaction can be observed most clearly with radical or ionic initiators. These are energy-rich compounds which can add suitable unsaturated compounds (monomers) and mainta 。

30、in the activated radical ，or ionic, state so that further monomer molecules can be added in the same manner 。
For the individual steps of the growth reaction one needs only a relatively small activation energy and therefore through a single activation step （the actual initiation reaction） a large num 。

31、ber of olefin molecules are converted ，as is implied by the term “chain reaction”. Because very small amounts of the initiator bring about the formation of a large amount of polymeric material （1：1000 to 1：1000）, it is possible to regard polymerization from a superficial point of view as a catalytic 。

32、 reaction 。
For this reason, the initiators used in polymerization reactions are often designated as polymerization catalysts ，even though, in the strictest sense, they are not true catalysts because the polymerization initiator enters into the reaction as a real partner and can be found chemically b 。

33、ound in the reaction product ,i.e 。

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标题：完整|(完整word版)高分子材料工程专业英语翻译( 三 )