What are the key polymeric structural features common to most ...

[chads108]

What are the key polymeric structural features common to most elastomeric materials?
 
  What will be an ideal response?

Question 2

Two crosslinkable polyesters are being considered for use as the resin in making a fiberglass-reinforced tank for processing various chemicals. One polyester is made from a glycol having four carbons between the alcohol groups and the other is made using the same acid but from a glycol having eight carbons between the alcohols. Compare the physical, chemical, and mechanical properties of the two resins. If the chemicals being processed are water-based, which resin is the best candidate on the basis of chemical resistance?
 
  What will be an ideal response?

[leahm14]

Answer to Question 1

Elastomers are generally linear, aliphatic materials with structures that do not pack together easily and are therefore noncrystalline. These materials have highly random structures in their relaxed state but will become more ordered if stretched.

Answer to Question 2

The material containing the four carbons will have a higher crosslinked density and as such will have a higher shrinkage and stiffness and resistance to chemicals than the material containing the eight carbon bonds. For the same reasons as mentioned, the four carbon bonded polyester will have a better resistance to the water-based chemicals.

[chads108]

Thank you!

[leahm14]

Always glad to help...