Discuss the physical factors in a plastic that affect ...

[mynx]

Discuss the physical factors in a plastic that affect permeability.
 
  What will be an ideal response?

Question 2

You are molding a toy bridge (6 inches high with a 24 inch span) that is failing (bending) when kids step on the span. The part is currently made of a plastic with a melt index of 10 and a density of 0.94 . The market is highly competitive, so ideal solutions should take cost into account. Indicate 4 possible methods of solving the problem, and then choose one of the methods and defend your choice.
 
  What will be an ideal response?

[ntsoane kedibone]

Answer to Question 1

The tightness or denseness of the polymer structure is one of the most important physical factors affecting permeability. Therefore, crystallinity reduces permeability. Likewise, crosslinking reduces permeability. Other factors affecting permeability would be the similarity of chemical natures between the polymer and the gas passing through. If these are similar, permeability is increased. Other factors affecting permeability include temperature (increases permeability) and size of the permeating molecules

Answer to Question 2

Possible answers include thickening the bridge in key areas, finding a material with higher melt index or higher density, or even using mold-in supports. Answer should also include a valid discussion of the chosen solution.

[mynx]

TY

[ntsoane kedibone]

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