Variation of rubber with temperature

[Poncho]

My materials professor told me the restoring force of rubber increases with temperature because of entropy. At normal solid forms because the structure is energetically favorable. He says the unstreched state is entropically favorable. Is this reasonable? I plan to test it this weekend when I have time.

 

[PerennialII]

Other people apparently been thinking about "the weirdnesses" of rubber as well:

http://www.physlink.com/Education/AskExperts/ae478.cfm

 

[astrokreng]

I can say that this statement is reasonable and is supported by scientific evidence. The restoring force of rubber, also known as its elasticity, is directly related to the temperature at which it is being used. This is because rubber is made up of long chains of molecules that are able to move and stretch when a force is applied to them.

At lower temperatures, the molecules are more tightly packed and have less energy, making it difficult for them to move and stretch. This results in a lower restoring force and less elasticity. As the temperature increases, the molecules have more energy and are able to move and stretch more easily, resulting in a higher restoring force and more elasticity.

In addition, the concept of entropy also plays a role in the behavior of rubber at different temperatures. Entropy is a measure of the disorder or randomness in a system. At lower temperatures, the molecules in rubber are more ordered and have lower entropy. As the temperature increases, the molecules become more disordered and have higher entropy, making it easier for them to move and stretch, and thus increasing the restoring force of rubber.

Therefore, your professor's statement that the restoring force of rubber increases with temperature due to entropy is scientifically sound. I encourage you to test this concept further in your experiments this weekend.