高分子专业英语课文翻译(7)

十分清楚。

UNIT 3 Step-Growth Polymerization

第三单元 逐步聚合

Many different chemical reactions may be used to synthesize polymeric

materials by step-growth polymerization. These include esterification, amidation, the formation of urethanes, aromatic substitution, etc. Polymerization proceeds by the reactions between two different functional groups, e.g., hydroxyl and carboxyl groups, or isocyanate and hydroxyl groups.

许多不同的化学反应通过逐步聚合可用于合成聚合材料。这些反应包括酯化、酰胺化、

氨基甲酸酯、芳香族取代物的形成等。通过反应聚合反应在两种不同的官能团，如，羟基和羧基，或异氰酸酯和羟基之间。

All step-growth polymerization fall into two groups depending on the type of

monomer(s) employed. The first involves two different polyfunctional monomers in which each monomer possesses only one type of functional group. A polyfunctional monomer is one with two or more functional groups per molecule. The second involves a single monomer containing both types of functional groups. The synthesis of polyamides illustrates both groups of polymerization reactions. Thus, polyamides can be obtained from the reaction of diamines with diacids

所有的逐步聚合反应根据所使用单体的类型可分为两类。第一类涉及两种不同的官能

团单体，每一种单体仅具有一种官能团。一种多官能团单体每个分子有两个或多个官能团。第二类涉及含有两类官能团的单种单体。聚酰胺的合成说明了聚合反应的两个官能团。因此聚酰胺可以由二元胺和二元酸的反应或氨基酸之间的反应得到。

nH2N-R-NH2+nHO2C-R’-CO2H→

H-(-NH-R-NHCO-R’-CO-)n-OH+(2n-1)H2O (3.1)

or from the reaction of amino acids with themselves

nH2R-CO2H→ H-(-NH-R-CO-)n-OH+(n-1)H20 (3.2)

The two groups of reactions can be represented in a general manner by the equations as follows

A+B-B →–[-A-A-B-B-]-A-B→–[-A-B-]-

两种官能团之间的反应一般来说可以通过下列反应式表示

反应式略

Reaction (3.1) illustrates the former, while (3.2) is of the latter type.