April 15, 2000 |
Diagnostic Quiz in Polymer Processing Basics
2. Write the continuity equation. What basic principle does this equation represent?
3. In a stress relaxation experiment, a cylinder of material is instantaneously stretched from length Lo to length Lf and held at Lf. Sketch qualitatively the tensile stress as a function of time which is required to maintain this deformation for a) an elastic solid; b) a viscoelastic solid; and c) a Newtonian liquid. 4. Give one specific example of a chain-growth polymerization reaction.
5. Sketch the tensile modulus as a function of temperature for a typical non-crystallizable thermoplastic polymer. Identify particular regions of interest on the curve.
6. Velocities u and v in a flow in the x-y plane are governed by the following pair of partial differential equations: 7. A long, narrow slab of hot amorphous polymer of width W at temperature Ti is quenched into a large water bath at Twater at time=0. Sketch how you would expect the temperature distribution within the slab to vary as a function of time and distance x from the centerline of the slab. |