1. Sketch portions of a linear polypropylene molecule that are (a) syndiotactic, (b)atac- tic, and (c) isotactic.
2. Sketch cis and trans structures for (a) buta- diene, and (b) chloroprene.
3. Make comparisons of thermoplastic and thermosetting polymers (a) on the basis of mechanical characteristics upon heating, and (b) according to possible molecular structures.
4. (a) Is it possible to grind up and reuse phenol-formaldehyde? Why or why not?
(b) Is it possible to grind up and reuse polypropylene? Why or why not?