Which is stronger: Glue or tape? - Elizabeth Cox

翻译人员: 宽 彭 校对人员: Monkey Luffy

The oldest glue in the world is over 8,000 years old

最古老的胶在 8000 年 之前就已经出现了，

and comes from a cave near the Dead Sea.

来源于死海附近的某处洞穴。

Ancient people used this glue,

古人用这些由兽骨和 植物原料的混合物制成的胶，

made from a mixture of animal bone and plant materials,

to waterproof baskets and construct utensils.

做防水的篮子和建筑用具。

And for thousands of years after,

几千年之后，

plants and animals were the glue that held human civilization together.

植物和动物仍是 将人类文明连接起来的“胶”。

Today, we have enough types of tape and glue to build and repair almost anything.

如今，我们有种类充足的胶水和胶带 来建造和修复几乎任何东西。

But what gives glue and tape their stickiness?

但是什么赋予了胶带和胶水粘性呢？

And is one stronger than the other?

是否其中一个的粘性比另一个强呢？

Adhesives can be made from synthetic molecules

粘着剂可以由人造分子

or natural proteins and carbohydrates

或天然蛋白和碳水化合物制作而成。

like the vegetable starch dextrin,

比如植物淀粉，糊精，

the milk protein casein,

又如牛奶蛋白——酪蛋白

and the terpenes in tree resin.

和树脂中的萜烯。

In order to work, glue and tape need both adhesive bonds and cohesive bonds.

为了发挥作用，胶水和胶带

需要粘合纽带和聚合纽带。

Adhesive bonds occur between an adhesive’s molecules

粘合骨架形成于粘着剂分子，

and the molecules of whatever it’s sticking to.

和与它粘连的任意分子之间

Cohesive bonds happen between a glue or tape’s own molecules,

聚合纽带发生于

胶带或者胶水自身分子之间，

holding it together.

将他们聚合。

Most glues consist of adhesive polymers dissolved in a solvent

大部分的胶水由溶于溶剂的

黏着聚合物组成，

that prevents them from sticking to the inside of the bottle.

防止它们粘附在容器的内壁。

The strong smell of many glues comes from the solvent,

许多胶水强烈的气味 来自于它的溶剂，

which evaporates when exposed to air.

当暴露于空气中时会发生挥发；

Some glues use water as a solvent,

有些胶水用水来当溶剂，

but others use chemicals that can be harmful to inhale.

其它则用吸入有害的化学试剂来当溶剂。

Glues with two or more components that chemically react instead of just drying

含有两种或更多成分，不仅仅是变干

还能发生化学反应的胶水，

can create stronger bonds.

可以创造更强的纽带。

Both the adhesive and cohesive bonds of glue are strong,

胶水的聚合纽带和粘合纽带都很强，

but the drying process makes them irreversible.

但是干燥的过程使得它们不可逆，

This is why, if a glued surface is broken after it dries,

这就是为什么，如果一个

涂有胶水的表面在其干燥后破裂，

it can’t be reattached without new glue.

没有新的胶水它就不能重新附着。

By contrast, when tape is applied to a surface,

相反的，当胶带被用于一个表面，

it forms weaker, reversible bonds,

它形成弱的，可逆的纽带，

so you can peel a piece of tape off a surface and use it again.

所以你可以从表面撕一片

胶带下来并重新使用它。

These weak bonds, called Van der Waals forces,

这些弱的纽带名为范德华力，

can occur between any two materials,

发生于任意两种材料之间，

but only if they’re extremely close together,

但只在两者极其接近时起作用，

closer than the naked eye can see.

比肉眼可见还要更近。

Tape usually consists of a backing coated with a combination of a rubber

胶带通常由包被了聚合物的附着物，

or rubber-like "stretchy" component,

如橡胶聚合物或是

橡胶状的有弹性的聚合物，

and a compound called a tackifier.

和一种名为增粘剂的化合物组成，

That’s the "sticky" component.

这就是所谓的粘性组分。

A tape’s stickiness is determined

一个胶带的粘性取决于

by the proportion of elastic component and tackifier,

弹性成分和增粘剂的比例、

the thickness of adhesive spread onto the backing,

和粘着剂在附着物上的扩散厚度、

and the type of backing material.

以及附着物材料的种类。

No chemical reaction occurs when tape is pressed onto a surface.

当胶带被铺展在表面上，

没有化学反应的发生。

Instead, the soft adhesive flows into the cracks and grooves of the surface.

相反的，柔软的粘着剂

流入表面的缝隙和凹槽之中，

This ability to slide into cracks and then stay in place is called viscoelasticity.

这种流入缝隙并保留的能力 被称做粘弹性。

Once the viscoelastic adhesive fills these microscopic crevices,

一旦具有粘弹性的粘着剂

充满了这些微小的裂缝，

it is close enough to form Van der Waals forces.

距离近到足够产生范德华力。

So what’s the world’s strongest adhesive?

所以，什么是世界上最强的粘着剂？

Well, there’s no one answer.

好吧，其实没有答案。

In terms of absolute strength of adhesive bonds,

就粘着纽带的绝对力量而言，

glue is stronger than tape,

胶水要强过胶带，

but no single adhesive works well in all circumstances.

但没有单独的一种粘着剂

能适用于所有环境，

Of the glues, cyanoacrylates, or super glues,

对于胶水，氰基丙烯酸酯，或是万能胶，

may form the strongest bonds,

它们或许能产生最强的纽带，

but two-component epoxy glues have much higher resistance to heat and shearing,

但双组分环氧树脂胶水

对热和剪切有更高的抗性，

and are compatible with a wider range of surfaces.

并且与更广泛的表面相匹配。

So, if you wanted to dangle an anvil in the air,

所有如果你想把一个铁砧悬挂在空中，

super glue might be your best bet.

万能胶或许是你最好的选择。

But if you’re doing so over an active volcano,

但如果你想在活火山这样做，

you’d want an epoxy instead.

相反的，你会需要环氧树脂胶。

And in order to work at all,

并且为了起效充分，

glues need enough real estate where surfaces touch.

胶水需要足够的接触面积，

If for some reason you wanted to make a chain of bowling balls,

如果某些理由促使你去做一串保龄球，

duct tape would be better.

管道胶带会更加合适。

Engineers weigh similar, if less absurd, factors all the time.

工程师也是如此权衡问题，

要少出错，就应考虑所有因素。

Choosing the right glue to withstand the heat inside an engine

选择合适的胶水来忍受引擎中的热量，

is a matter of life and death.

是十分重要的事情！

And though the strength of duct tape’s adhesive bonds

尽管管道胶带粘着纽带的力，

can’t compete with those of epoxy glues,

不能与环氧树脂胶水的力相媲美，

tape does have the advantage of instantaneous stickiness in an emergency.

但胶带确实有着

能够在紧急情况下

立马产生粘性的优势。

Glue may be necessary to get a rocket to space,

为了将火箭运送到太空，胶水是必需的；

but when it comes to extraterrestrial repairs,

但在地外维修的过程中

stick to duct tape: liquid glues don’t work in zero gravity.

用管道胶带吧，液体胶水

在失重环境下无法工作。