自由基聚合的实施方法

1、自由基聚合的实施方法Techniques of free radical polymerization教学设计 教学内容与设计时间分配或备注说明A number of chain-growth polymers are commercially produced on a large scale, and the technology of polymerization deserves some comment.参考译文：目前已经采用连锁聚合大规模的生产了很多的聚合物，因此，聚合的实施方法值得讨论一下。We shall discuss four polymerization techniqu

2、esBulk polymerization1、A bulk polymerization may be conducted with as few as two components: monomer and initiator. Production polymerization reactions are carried out to high conversions which produces several consequences.参考译文：本体聚合只有两个组分：单体和引发剂。本体聚合反应的单体转化率很高，这会产生一些影响。本体聚合是单体本身在不加溶剂以及其它分散剂的条件下，由引发

3、剂或直接由光热等作用下引发的聚合反应，优点：产品纯度高，尤其可以直接制得透明制品，聚合设备简单。缺点：体系粘度大，聚合热不易扩散，反应难以控制，易局部过热，造成产品发黄。自动加速作用大，严重时可导致爆聚。 Solution Polymerization1、Solution polymerization is the name given to the technique of polymer formation in the presence of a solvent. The polymer may not have the same solubility in the solvent as

4、 the monomer, so the system may become heterogeneous with the formation of polymer.参考译文：溶液聚合是聚合物的生成过程中加入了溶剂。生成的聚合物在溶剂中的溶解度与单体不同，因此，随着聚合物的生成，体系会变成非均相的。2、Although there is an increase in viscosity as polymer concentration in the system increases, the effect is mitigated by the presence of solvent, and

5、 autoacceleration through the Trommsdorff mechanism is less troublesome than in bulk polymerizations. This permits easier stirring and better heat exchange than in the bulk.参考译文：尽管随着聚合物浓度的增加，体系的粘度逐渐增加，但是溶剂会使体系的粘度下降，而且，和本体聚合相比，自动加速效应会降低，体系更容易搅拌，聚合热更容易扩散。3、The solvent is ordinarily chosen to show no c

6、hain transfer so that high molecular weight polymer is obtained. Solvent recovery must be considered as part of the overall process and this, of course, adds to the cost of this method.参考译文：为了得到高分子量的聚合物，一般要选择不发生链转移的溶剂。在生产过程中，一定要考虑溶剂的回收问题，当然，这会使溶液聚合的成本增加。Suspension Polymerization1、A technique called

7、suspension polymerization is sometimes employed with water-insoluble monomers. In this procedure the monomer is suspended by agitation as small drops in an aqueous medium. 参考译文：采用悬浮聚合实施方法的单体不溶于水，单体在搅拌下以小液滴的形式分散在水中。2、The diameters of the drops are in the range of micrometers to millimeters in this te

8、chnique. Coalescence of the monomer drops is prevented by stirring and by addition of water-soluble polymers like gelatin or by suspending clay particles like kaolin in the mixture.参考译文：悬浮聚合中，小液滴的直径在微米和毫米之间。搅拌和加入水溶性高分子明胶和不溶于水的粘土如高岭土等可以防止单体小液滴的聚集。 Emulsion PolymerizationThe fourth and most interestin

9、g of the polymerization techniques we shall consider is called emulsion polymerization参考译文：第四种和最有趣的聚合实施方法是乳液聚合1、It is important to distinguish between suspension and emulsion polymerization, since there is a superficial resemblance between the two and their terminology has potential for confusion: A

10、 suspension of oil drops in water is called an emulsion. Water-insoluble monomers are used in he emulsion process also, and the polymerization is carried out in the presence of water.参考译文：区分悬浮和乳液聚合非常重要，因为它们表面上很相似，名词也很容易混淆：悬浮在水中的油滴叫乳状液。乳液聚合中的单体也是不溶于水的，反应也是在水介质中进行的。 2、Emulsion polymerization also has

11、the advantages of good heat transfer and low viscosity, which follow from the presence of the aqueous phase. The resulting aqueous dispersion of polymer is called latex.参考译文：乳液聚合由于在水相中进行，它的优点是聚合热容易扩散和体系粘度低。聚合物分散在水中叫做胶乳。3、The polymer can be subsequently separated from the aqueous portion of the latex or the latter can be used directly in eventual applications. 参考译文：聚合产物可以直接从乳状液中分离出来或者可以直接使用。【总结】 本篇需要掌握的单词，词组和句子Words and Expressions: