From DNA to Silly Putty: The diverse world of polymers - Jan Mattingly

翻译人员: Xiaoyu Ye 校对人员: Mingyu Cui

What do silk,

丝绸，

DNA,

wood,

DNA，

balloons,

木材，

气球，

and Silly Putty all have in common?

和橡皮泥有什么共同点？

They're polymers.

它们都是高分子聚合物(polymer)，简称高聚物。

Polymers are such a big part of our lives

高聚物是生活中一个十分重要的部分，

that it's virtually impossible

没有高聚物的世界

to imagine a world without them,

是不可想象的。

but what the heck are they?

但它们到底是什么？

Polymers are large molecules

高分子聚合物是大分子物质，

made of small units called monomers

由单分子物质(monomer)聚合而成，

linked together like the railroad cars from a train.

连接起来像是一节节车厢连成火车。

Poly means many,

它的英文中“Poly”的意思是多，

and mono means one,

“mono”意思是单，

and mers or mero means parts.

“mers”或“mero”是“一部分”的意思。

Many polymers are made by repeating

许多高聚物由

the same small monomer over and over again

相同单分子物质重复形成，

while others are made from two monomers

有的由两种单分子

linked in a pattern.

按照一定模式连接。

All living things are made of polymers.

所有生物都由高分子聚合物组成。

Some of the organic molecules in organisms

有些生物体内的有机物

are small and simple,

小而简，

having only one of a few functional groups.

只有很少一些功能单元。

Others, especially those that play structural roles

其它功能，尤其作为结构功能

or store genetic information,

或保存基因信息的单元，

are macromolecules.

都是大分子物质。

In many cases, these macromolecules are polymers.

大部分情况下这些大分子都是高聚物。

For example, complex carbohydrates

举个例子，复杂的碳水化合物

are polymers of simple sugars,

都是简单糖类的高分子聚合；

proteins are polymers of amino acids,

蛋白质是氨基酸的高分子聚合；

and nucleic acids, DNA and RNA,

核酸，包括脱氧核糖核酸以及核糖核酸，

which contain our genetic information,

它们包含了我们的遗传信息，

are polymers of nucleotides.

是核苷酸的高分子聚合形式。

Trees and plants are made

树木等等植物是由

of the polymer cellulose.

高聚物纤维素组成，

It's the tough stuff you find in bark and stems.

它们是树皮和茎的坚硬组分。

Feathers,

羽毛，

fur,

hair,

毛皮，

and fingernails

毛发，

以及指甲，

are made up of the protein keratin,

都由同一种蛋白质角蛋白组成，

also a polymer.

它也是种高聚物。

It doesn't stop there.

还有更多类似的例子：

Did you know that the exoskeletons

你知道在动物学中

of the largest phylum in the animal kingdom,

最大的门的动物的外骨骼

the arthropods,

节肢动物的外骨骼，

are made of the polymer chitin?

是由高聚物几丁质组成的吗？

Polymers also form the basis

高分子聚合物还包括了

for synthetic fibers, rubbers, and plastics.

合成纤维，合成橡胶以及塑料。

All synthetic polymers are derived from petroleum oil

所有合成的高聚物都源于石油，

and manufactured through chemical reactions.

通过一系列化学反应合成。

The two most common types of reactions

最常见的两种用来

used to make polymers

制造高聚物的反应

are addition reactions

and condensation reactions.

是加成反应

和缩聚反应。

In addition reactions,

在加成反应中，

monomers simply add together to form the polymer.

单分子简单的加在一起形成高聚物。

The process starts with a free radical,

过程从产生一个自由基开始，

a species with an unpaired electron.

自由基是带有一个未成对电子的基团。

The free radical attacks

and breaks the bonds to form new bonds.

自由基攻击其它基团，

断开化学键以形成新键。

This process repeats over and over

这个过程不断重复，

to create a long-chained polymer.

逐渐形成了长链高聚物。

In condensation reactions,

在缩聚反应中，

a small molecule, such as water,

小分子比如水分子，

is produced with each chain-extending reaction.

将经过每一个链延伸反应。

The first synthetic polymers

第一个合成高聚物

were created by accident

是偶然间创造出来的，

as by-products of various chemical reactions.

它是几个化学反应的副产物。

Thinking they were useless,

那时候许多化学家认为它们没用，

chemists mostly discarded them.

大部分就丢弃了。

Finally, one named Leo Baekeland

直到有个化学家利奥・贝克兰德

decided maybe his useless by-product

认为也许这没用的副产物

wasn't so useless after all.

并非一无是处。

His work resulted in a plastic

他研究下去并制造了一种塑料，

that could be permanently squished into a shape

可以永久地形成任何一种形状，

using pressure and high temperatures.

只要有足够的压力和高温。

Since the name of this plastic,

然而这种塑料的名字，

polyoxybenzylmethylenglycolanhydride,

polyoxybenzylmethylenglycolanhydride

wasn't very catchy,

太长了，

advertisers called it Bakelite.

商人们把它称作贝克莱特（酚醛塑料）。

Bakelite was made into telephones,

这种塑料后来制成了电话，

children's toys,

儿童玩具，

and insulators for electrical devices.

以及电子产品的绝缘体。

With its development in 1907,

自从1907年发现了它，

the plastics industry exploded.

塑料工业发生了爆炸式发展。

One other familiar polymer, Silly Putty,

另外一种熟悉的高聚物，橡皮泥，

was also invented by accident.

也是偶然发明的。

During World War II,

the United States was in desperate need

在第二次世界大战中，

美国十分迫切的需要

of synthetic rubber to support the military.

合成橡胶来支持军队。

A team of chemists at General Electric

通用电气公司的一队化学家

attempted to create one

曾尝试制造，

but ended up with a gooey, soft putty.

但最终只得到了一种软黏的油泥。

It wasn't a good rubber substitute,

它并不能作为橡胶的好替代物，

but it did have one strange quality:

但它的确有一个奇怪的特性：

it appeared to be extremely bouncy.

它的弹性十分优良。

Silly Putty was born!

橡皮泥诞生了！

Synthetic polymers have changed the world.

合成高聚物已经改变了整个世界。

Think about it.

想想看，

Could you imagine getting through a single day

你能想象有这么一天

without using plastic?

不使用任何塑料吗？

But polymers aren't all good.

但不是所有高聚物都是好的。

Styrofoam, for example, is made mainly of styrene,

举个例子，泡沫塑料主要由苯乙烯合成，

which has been identified as a possible carcinogen

而苯乙烯被环保部认定为一种潜在致癌物。

by the Environmental Protection Agency.

As Styrofoam products are being made,

随着泡沫塑料的生产，

or as they slowly deteriorate in landfills or the ocean,

它们缓慢的使得土壤和海水恶化，

they can release toxic styrene

它们会释放苯乙烯到环境中。

into the environment.

In addition, plastics that are created

此外，塑料由加聚反应产生，

by addition polymerization reactions,

like Styrofoam,

比如泡沫塑料，

plastic bags,

塑料袋，

and PVC,

聚氯乙烯材料，

are built to be durable and food-safe,

它们能长久保存且不污染食物。

but that means that they don't break down

但这同样意味着它们在自然环境中

in the environment.

不会自行分解。

Millions of tons of plastics

每年成千上万吨的塑料

are dumped into landfills every year.

被丢弃到土壤中。

This plastic doesn't biodegrade,

这些塑料不会生物降解，

it just breaks down

它们只会分解成

into smaller and smaller pieces,

较小的碎片，

affecting marine life

and eventually making their way back to humans.

影响海洋生物，

最终伤害到人类。

Polymers can be soft or hard,

高聚物可软可硬，

squishy or solid,

fragile or strong.

可湿软可坚固，

可脆弱可强硬。

The huge variation between

这些巨大的差异

means they can form

意味着它们能形成

an incredibly diverse array of substances,

极其广泛的不同种物质，

from DNA

to nylon stockings.

从DNA

到尼龙丝袜，

Polymers are so useful

高聚物十分重要，

that we've grown to depend on them every day.

以至于我们每天都十分依赖。

But some are littering

但有些正在污染

our oceans, cities, and waterways

我们的海洋，城市，以及水源，

with effects on our health

最终威胁到我们的健康。

that we're only beginning to understand.

而这一点我们才刚刚理解。