This topic contains a solution. Click here to go to the answer

Author Question: Based on the chemical structures and make-ups of polyurethane and polystyrene, how would the flame ... (Read 26 times)

jazziefee

  • Hero Member
  • *****
  • Posts: 505
Based on the chemical structures and make-ups of polyurethane and polystyrene, how would the flame tests of these two materials differ? What would you expect to happen in the presence of a flame source? Describe flame color, smoke characteristics, and overall flammability.
 
  What will be an ideal response?

Question 2

How does high crystallinity in a resin affect the way the resin must be injection molded? Consider each of the stages in the process, i.e. from hopper to post-handling. What are the effects of narrowing molecular weight distributions?
 
  What will be an ideal response?



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

yasmin

  • Sr. Member
  • ****
  • Posts: 319
Answer to Question 1

Polystyrene contains a benzene ring which helps determine the characteristics of this material. In a flame in will burn readily and have a yellow flame that is dark and gives off sooty smoke.
Polyurethane contains two monomers with at least two reactive groups. As a thermoset or elastomer it has a poor high temperature stability which leads to the

belief that it is flammable and would burn bright with less smoke or none, and would be black and sooty.

Answer to Question 2

The higher the crystallinity the higher the possibility for shrinkage, so the injection pressure would probably need to be increased and an increase in holding time.




yasmin

  • Sr. Member
  • ****
  • Posts: 319

 

Did you know?

Pink eye is a term that refers to conjunctivitis, which is inflammation of the thin, clear membrane (conjunctiva) over the white part of the eye (sclera). It may be triggered by a virus, bacteria, or foreign body in the eye. Antibiotic eye drops alleviate bacterial conjunctivitis, and antihistamine allergy pills or eye drops help control allergic conjunctivitis symptoms.

Did you know?

There are major differences in the metabolism of morphine and the illegal drug heroin. Morphine mostly produces its CNS effects through m-receptors, and at k- and d-receptors. Heroin has a slight affinity for opiate receptors. Most of its actions are due to metabolism to active metabolites (6-acetylmorphine, morphine, and morphine-6-glucuronide).

Did you know?

The FDA recognizes 118 routes of administration.

Did you know?

Asthma cases in Americans are about 75% higher today than they were in 1980.

Did you know?

Barbituric acid, the base material of barbiturates, was first synthesized in 1863 by Adolph von Bayer. His company later went on to synthesize aspirin for the first time, and Bayer aspirin is still a popular brand today.

For a complete list of videos, visit our video library