Assignment

1. Viscosity is an important property of a polymer melt in plastics shaping processes. Upon what three parameters does viscosity depend?
2. How does the viscosity of a polymer melt differ from most fluids that are Newtonian?
3. What does viscoelasticity mean, when applied to a polymer melt?
4. Which one of the following is the chemical formula for the repeating unit in polyethylene:
   1. CH₂
   2. C₂H₄
   3. C₃H₆
   4. C₅H₈
   5. C₈H₈
5. Use of a parison is associated with which one of the following plastic shaping processes:
   1. bi-injection molding
   2. blow molding
   3. compression molding
   4. pressure thermoforming