rubber and elastomer. What we can designate as "elastomer"

Neither term has a very strong, well defined definition. They can be used interchangably at times.

To me, rubber means a chemically-crosslinked polymer, often based on natural rubber.

To me, elastomer means a "crosslinked" polymer, with the crosslinks being chemical or physical in nature, such as the phase separation seen in styrenic block copolymers. As such, all rubbers are elastomers, but not all elastomers are rubbers.

John

AFAIK are rubbers chemical crosslinked elastomers.. and TPE are elastomerst too, but they are no rubbers...

irt seems hat your question ist the same as the diffrenzce between female americans and americans....

Michael I am not a bug I am a undocumented feature

I am plastics engineers, the definition of an elastomers are natural or synthetic polymeric material that can be stretched to atleast 200 times their original length at room temp., and return quickly to their original length. So to answer your question, rubber is an elastomer because, it is originally a polymer added with additives to make it an elastomer.

This answer is seriously wrong.

I won't even ask what "official" source that you obtained your definition from, because it is seriously lacking, even if I grant you a typo for the minimum degree of extension required.

Leave the self-proclaimed "plastics engineers" for other to decide.

John

Go read "Industrial Plastics", theory and applications by Richardson pg 5. I am not a self proclaimed plastics engineer, i got the diploma from BCIT. The definition i gave out is a general defiinition for all elastomers. As for rubbers, the elasticity is determined by the amount of sulfer in added for crosslinking, more the stiffer.

sorry pg 13

perhaps 200% ? but I think at least 10 % and then you´ll leve the Hook area...

Some TPE with Shore D just dont reach 100% without permanent deformation...

I Know the definiton: Glasstransition lower than room temperature = elastomers higher than for example 100°C thermoplastics or duroplatics but some writes

I am not a bug I am a undocumented feature

u are right. i meant 200%. it was just a general definition.

deformation...

You really missed the points that I was making. First, the 200x definition that you wrote is extremely incorrect and it wasn't until your third follow-up post that you admitted the error. That is the most grevious error that you made in your original post, yet the last to be corrected.

Secondly, I am still not interested in who you refer to as a higher authority for the definition of "elastomer". While there are people and organizations that are trying to define it, the term as used by people in the industry includes a very wide range of materials that do or do not meet the definition that you cited. If you do not beliveve me, just do a google search for the terms "elastomer" and "definition". You will find most definitions do not agree with what you proposed. Given this, you can either take the position that you and Richardson are the right ones and the rest of the world is wrong, or you can try and deal with the vagueness of the term as most people use it. The choice is yours.

Lastly, if you look through even a few weeks worth of posting on this or any other "sci.*" newsgroup, you will find that people do not start their posts by "I am a _______________". Nobody really cares how many letters you have after your name or where you went to school. If you can provide the facts or helpful suggestions, you will be welcomed and appreciated. If not, than you will be refuted and or ignored at every turn, often savagely. (Search the newsgroups for a few of Uncle Al's post to really see a heated putdown). It is appreciated that you are trying to help, but you really need to be correct in your postings or you are not being helpful since the original poster won't be able to you are wrong. Again, the choice is yours.

John

no the question was the diffrence between elastomer and rubber...

Brice gave a definition of elastomer which will not necessary be reached by rubber, the others said that rubber is a special group in the elastomers...

so that every rubber is an elastomer

the definition of Brice says: may be that ruber is an elastomer

by the way sepcial for Brice: I hold a diploma in physics and since ´97 with TPE...

Your question was quite intressting for me because of an special experiment they did when we was in elemntary school, since then I am intrestid in categorizing and this is a realy nice question..

Michael I am not a bug I am a undocumented feature

Yes Michael rubber is an elastomer, the elasticity depends on the amount of sulfer added in the crosslinking.

elastomers...

i thought that there is even the possibilizy to use peroxides to start the crosslinking

I am not a bug I am a undocumented feature