1. 1. Compare three types of polymers, molecule structure, crystalline structure, stress-strain curves? materialsthermoplasticsthermosetselastomers Molecule structure Crystalline structure Stress- strain curve Explain strength and ductility on the curves

2. 2. Compare the crystal structure, stress- strain curve between metals and polymers

3. Mounting Mounting is required when (1) sample is small or oddly shaped to be handled.(2) The sample edge area needs to be examined. Thermal mounting : The sample is embedded in thermosetting plastics at elevated temperatures and pressure. 3. Class discussion Polymers-forming

4. Cold mounting: The sample is embedded in epoxy type of materials. Class discussion Polymers-forming

5. 4. What type(s) of bonding would be expected for each of the following materials? Ni-Cu alloy: Fe: NaCl: Si wafer: Polyetyer [-(CH 2 ) m CH 2 -O-]: MgO:

6. 5. What properties would be expected for each of the following materials? Materials ConductivitydensityCorrosionMelt point Ni-Cu alloy MgO Polyetyer Si wafer

7. 6. Indicate whether statements are true or false ① Polyester and epoxy are examples of thermosets ② It has been estimated that over three- quarters of all matrices of PMCs are thermosets.

8. 7. Mark the correct completions ① Thermosetting polymers a)are also known as thermoplastic polymers, b)are also known as rubbers, c)Readily cross-link during curing, d)Cannot be cured, e)Cannot be reheated and reshaped. ② Thermoplastics a)Are cross-linked polymer, b)Are linear polymers, c)May have branched chains, d)Readily flow at elevated temperatures, e)Cannot be reheated and reshaped. ③ Compared with a ceramic, a polymer normally has a (a)Greater strength, (b)Lower stiffness, (c)Lower density, (d)Better high temperature performance, (e)Lower hardness.