destroyed

[Kenny同志]

Natural rubber is an elastomer and a thermoplastic. However, it should be noted that once the rubber is vulcanized, it will turn into a thermoset. Most rubber in everyday use is vulcanized to a point where it shares properties of both; i.e., if it is heated and cooled, it is degraded but not destroyed.

Hello, I need a professional to explain this.

Being degraded means the quality/performance of the rubber becomes worse, but what would happen if it is destroyed?

Thanks in advance.

[jkhsu]

When the rubber is destroyed, then it is no longer rubber anymore whereas, when the rubber is degraded the quality/performance of the rubber is decreased but it can still function as rubber.

[jbradfor]

The case for rubber is a bit more complicated. [Although I'm no professional....]

(Natural) rubber, by itself, is very brittle, especially when cold. It was discovered (by accident) that if you heat (vulcanize) rubber, and then let it cool, it is much less brittle. However, doing so also "degrades" it in the sense that it is affected in other (bad) ways, such as it is not as tough and does not resist abrasion as well.

[Kenny同志]

Thanks for helping me out comrades!

PS: the source text is from the wiki entry "natural rubber" and you can find the Chinese translation on my blog.

[xiaocai]

Good work kenny. I think it's all to do with the elasticity (ability to restore to its original shape after forces have been applied to). Being destroyed means a complete loss of elasticity (thus, only deformation); whereas degradation means that it still functions as rubber but just has become less elastic (and partially deformable).

[jbradfor]

the source text is from the wiki entry "natural rubber"

:oops:

Well I'm pretty embarrassed then to be telling you about the properties of rubber, as after reading that article you already know more than I do.....

[jkhsu]

jbradfor - If you knew about vulcanization of rubber without having to look it up, then you have nothing to be embarrassed about. I don't remember reading about it in my materials science or mechanics of materials classes in college. If it was there, I've forgotten it by now.

[Kenny同志]

@xiaocai

Thanks xiaocai. In fact, the quality/performance of natural rubber involves a lot of parameters, elasticity being one of them. See this

@Jbradfor

Please don't be embarrassed. My major was polymer science but I had to ask for help to understand this simple fact.

A correction:

Vulcanization doesn't necessarily need heating though it is often applied in the vulcanization of many rubber products. Normally we can conclude that vulcanization occurs when a crosslinked network of rubber molecules is formed by the application of a certain curing agent.

[jbradfor]

Vulcanization doesn't necessarily need heating though it is often applied in the vulcanization of many rubber products.

Interesting.... and wikipedia agrees with you. I learn something new every day! The term "Vulcanization" comes from Vulcan (the god of fire); I always thought that this term referred only to heating things.

[skylee]

I thought Vulcan meant 火神星人 such as Spock.

[jbradfor]

Well, they are related. IIRC, "Vulcan" was also the name of a (proposed) planet whose orbit was closer to the sun than Mercury's. It was proposed to explain the observed orbit of Mercury, which didn't quite follow Newton's Law of Gravity. However, Einstein's special theory of relativity explained the orbit of Mercury and eliminated the need for this proposed planet. [And, as an aside, was early experimental validation for Einstein's theory.] Gene Roddenberry liked the story enough that he named Spock's homeworld after that.

But I digress