聚合物化学翻译_第一章

2021年2月12日发(作者：sequences)

BASIC CONCEPTS

A polymer is a large molecule built up from numerous smaller molecules. These large molecules

may

be

linear,

slightly

branched,

or

highly

interconnected.

In

the

latter

case

the

structure

develops into a large three-dimensional network.

聚合物是由数目众多的较小分子构造而成 的一种大分子。

这些大分子可以是线型的、

简单的

支链型的、或者是高度相互交联的。后者的结构发展成一种三维网状结构。

The

small

molecules

used

as

the

basic

building

blocks

for

these

large

molecules

are

known

as

monomers. For example the commercially important material poly(vinyl chloried) is made from

the monomer vinyl chloride. The repeat unit in the polymer usually corresponds to the monomer

from which the polymer was made.

构成大分子中基本单元的小分子被称为单体。

例如 ，

具有

重要商业用途的聚氯乙烯是由氯乙烯单体制成的。

聚合物中的重复结构单元常常相当于制成

聚合物的单体。

P1-2

There

are

exceptions

to

this,

though.

Poly(vinyl

alcohol)

is

formally

considered

to

be

made up of vinyl alcohol (CH2CHOH) repeat units but there is , in fact, no such monomer as vinyl

clcohol.

< /p>

虽然也有例外。

聚乙烯醇一般会被认为是由乙烯醇这种重复单元制 成的，

但是，

事实上没有

乙烯醇这样一 种单体。

The

appropriate

molecular

unit

exists

in

the

alternative

tautomeric

form,

ethanal

CH3CHO.

To

make this polymer, it is necessary first to prepare poly(vinyl ethanoate) from the monomer vinyl

ethanoate, and then to hydrolyse the product to yield the polymeric alcohol.

相应的分子单元以 互变异构的形式

-

乙醛存在。为了制备聚乙烯醇，必需先由乙酸 乙烯酯单

体制备出聚乙酸乙烯酯，然后对产品进行水解最终制成聚乙烯醇。

The

size

of

a

polymer

molecule

may

be

defined

either

by

its

mass

(see

Chapter

6)

or

by

the

number

of

repeat

units

in

the

molecule.

This

latter

indicator

of

size

is

called

the

degree

of

polymerization,

DP

.

The

relative

molar

mass

of

the

polymer

is

thus

the

product

of the

relative

molar mass of the repeat unit and the DP

.

聚 合物分子的尺寸既可以被定义为它的质量也可以

被定义为它的分子重复单元的数量。

后者被称为聚合度。

因此聚合物的相对分子质量是重复

单元和聚合度的相对摩尔质量的产物。

There is no clear cut boundary between polymer chemistry and the rest of chemistry. As a very

rough

guide,

molecules

of

relative

molar

mass

of

at

least

1000

or

a

DP

of

at

least

100

are

considered to fall into the domain of polymer chemistry.

< p>
在聚合物化学和其它化学之间不存在严格的界线。

作为一个粗陋的指标，< /p>

分子的相对分子量

至少达到

1000

或聚合度至少

100

被认为是聚合物化学的 范畴。

The vast majority of polymers in commercial use are organic in nature, that is they are based on

covalent

compounds

of

carbon.

This

is

also

true

of

the

silicones

which,

though

based

on

silicon- oxygen backbones, also generally contain significant proportions of hydrocarbon groups.

商业中聚合物的绝大多数分子在性质上是有机分子，

也就是说这些聚合物是基于碳原子的共

价键化合物。对于硅氧烷聚合物也 是如此，尽管它们以硅

-

氧键为主链，一般也含有大量的

烷烃基团。

The

other

elements

involved

in

polymer

chemistry

most

commonly

include

hydrogen,

oxygen,

chlorine,

fluorine,

phosphorus,

and

sulfur,

i.e.

those

elements

which

are

able

to

form

covalent

bonds, albeit of some polarity, with carbon.

在聚合物化学中其它的元素包括氢、氧、氯 、氟、磷和硫，它们中有些是极性元素，但都能

与碳形成共价键。

As

is

characteristic

of

covalent

compounds,

in

addition

to

primary

valence

forces,

polymer

molecules are also subject to various secondary intermolecular forces. This include dipole forces

between

oppositely

charged

ends

of

polar

bonds

and

dispersion

forces

which

arise

due

to

perturbations of the electron clouds about individual atoms within the polymer molecule.

作为共价键化合物的 特性，

除了有主价键力之外，

聚合物分子也拥有多种第二分子间 作用力。

这种分子间力包括极性键相反电荷未端的极性力，

以及 色散力，

色散力来源于聚合物分子内

单个原子间电子云的扰动。

Hydrogen bonding, which arises from the particularly intense dipoles associated with hydrogen

atoms attached to electronegative elements such as oxygen or nitrogen, is important in certain

polymers, notably proteins. Hydrogen bonds have the effect of fixing the molecule in a particular

orientation. These fixed structures are essential for the specific functions that proteins have in

the biochemical processes of life.

氢原子靠近电负性元素如氧或氮，

会具有特别强的偶极，

由此产生氢键，

氢键对有些聚合物

比如蛋白质极为重要。

氢键具有把分子固定在某个特定取向上的作用。

这种固定结构至使蛋

白质在生命的生物化学过程中承担起特殊功能是十分必要的。

THE HISTORY OF THE CONCEPT OF THE MACROMOLECULE

Modern books about polymer chemistry explain that the word polymer is derived from the Greek

words ‘poly’ meaning many an ‘meros’ m

eaning part. They often then infer that it follows that

this term applies to giant molecules built up of large numbers of interconnected monomer units.

In fact this is misleading since historically the word polymer was coined for other reasons.

关 于聚合物化学的现代书藉解释聚合物

（

polymer

）

这个词汇是洐生于 希腊单词

‘

poly

’

，

它的意思是很多，单词‘

meros

’意思是部分。然后这些书推断跟随聚合物这个术语意味着

< br>巨大的分子，

由大量的相互连接的分子单元构建而成。

事 实上这是个误解，

聚合物这个单词

在历史上是为其它原因而构造 出来的。

The

concept

of

polymerism

was

originally

applied

to

the

situation

in

which

molecules

had

identical

empirical

formulae

but

very

different

chemical

and

physical

properties.

For

example,

benzene (C6H6; empirical formula also CH) was considered to be a polymer of acetylene (C2H2;

empirical formula also CH).

Thus the word

‘

polymer

’

is to be found in textbooks of organic

chemistry published up to about 1920 but not with its modern meaning.

起 初聚合的概念被应

用于这样的场景，分子具有相同的经验分子式但化学性质和物理性质极 其不同。例如，苯

(C6H6;

经验分子式

CH)

< br>被认为是乙炔的聚合物

‘

polymer

’

。

（

C2H2;

经验分子式

CH

）

因

此聚合物‘

polymer

’

这个单词在约

1920

年以前的有机化学教科书中一直都能找到，但却

不是现代这个含义。

< br>

The situation is confused, however, by the case of certain chemicals. Styrene, for example, was

known from the mid- nineteenth century as a clear organic liquid of characteristic pungent odour.

< br>可这在特定化学里是种被混淆的情形。

例如苯乙烯从十九世纪中期就被认定是一种 带特殊刺

激性气味的纯粹的有机液体。

It was also known to convert itself under certain circumstances into a clear resinous solid that

was almost odour-free, this resin then being called metastyrene. The formation of metastyrene

（介苯乙烯）

from styrene was described as a polymerisation and metastyrene was held to be a

polymer of styrene.

也知道苯自身在一定环境下会转化成没有气味的纯粹的树脂状固体。

由苯乙烯制 得介苯乙烯

的形成过程被定义为聚合，且介苯乙烯被称作是苯乙烯的聚合物。

< p>

P3-0

However

these

terms

applied

only

in

the

sense

that

there

was

no

change

in

empirical

formula despite the very profound alteration in chemical and physical properties. There was no

understanding of the cause of this change and certainly the chemists of the time had no idea of

what had happened to the styrene that was remotely akin to the modern view of polymerisation.

可是这些术语仅仅被用在经验分子式不发生变化的情况下，

虽然在化学性质和物 理性质上有

深刻的改变。

改变的原因无从理解，

且那个时代的化学家无法想象苯乙烯到底发生了什么变

化，这与相似于现代观念 中的聚合是如此的遥远。

Understanding

of

the fundamental

nature

of

those

materials

now

called

polymers had

to

wait

until

the

1920s, when Herman

Staudinger

coined

the word

‘macromolecule’

and thus

clarified

thinking. There was no ambiguity about this new term

–

it meant ‘large molecule’, again from the

Greek, and these days is used almost interchangeably with the word polymer. Strictly speaking,

though, the words are not synonymous.

要理解现在被称 为聚合物的这些物质的基本属性还必须等到十九世纪二十年代，在那时

Stauding er

造了个新单词

‘

macromolecule

’大分子以正视听。这个新单词的意思是大的分< /p>

子，

这样就不会模棱两可了，

‘

macromolecule

’

也来自于希腊语，

并且今天也和’

polymer

‘这个单词互换使用。从严格意义上说，这两个单词并不是同义 词。

P3-1

There

is

no

reason

in

principle

for

a

macromolecule

to

be

composed

of

repeating

structural units; in practice, however, they usually are.

Staudinger’s concept of macromolecules

was not at all well received

at first. His wife once recalled that he had ‘encountered opposition in

all his lectures’.

< br>从原理上说没有理由认为大分子一定是重复结构单元组成的，可是，大分子的确常常如此。

Staudinger

的大分子概念起初并未很好的被人们接受。一次他的妻子 回忆过去，说他在所有

的讲座中遭到反对。

Typical of this opposition was that of one distinguished organic chemist who declared that it was

as if zoologists ‘were told that somewhere in Africa an elephant was found who was 1500 feet

long and 300 feet high’.

反对者的一个典型例子是，

某位著名 有机化学家他声称，

大分子好比动物学家们被告知在非

洲发现一 头大象，它有

1500

英尺长

300< /p>

英尺高。

There

were

essentially

three

reasons

for

this

opposition.

Firstly,

many

macromolecular

compounds

in

solution

behave

as

colloids.

Hence

they

were

assumed

to

be

identical

with

the

then known inorganic colloids. This in turn implied that they were not macromolecular at all, but

were actually composed of small molecules bound together by ill-defined secondary forces.

有三个关键原因致使这些反对态度。

首先很多大分子在溶液中的表现很象胶体。

因此，

他们

被认这与已知的无机胶体是相同的东西。

反过来这又暗 示着他们完全不是大分子，

而实际上

是由定义不清的第二分子间 力结合在一起的小分子组成。

Such thinking led the German chemist C. D. Harries to pursue the search for the ‘rubber molecule’

in the early years of the twentieth century. He used various mild degradations of natural rubber,

which he believed would destroy the colloidal character of the material and yield its constituent

molecules, which were assumed to be fairly small. He was, of course, unsuccessful.

这种思潮影响德国化学家

Harries

在二十世纪早期去寻找所谓的’

橡胶分子’

。

他使用各种各

样天然 橡胶的温和的降解物，

在其中他相信破坏了材料的胶体性质并且生成了胶体的组成分

子，此组成分子被认为是非常小的。当然，他不会成功。

The second reason for opposition to Staudinger’s hypothesis was that it meant

the loss of the