Page 56 - Carrahers_Polymer_Chemistry,_Eighth_Edition

Introduction to Polymers 19

Elastomer: A rubber.
Environmental impact assessment (EIA): An assessment of the possible impact that a project
or material may have on the natural environment.
Filament: The individual extrudate emerging from the holes in a spinneret; forms fi bers.
Functionality: The number of reactive groups.
Intermolecular forces: Secondary forces between macromolecules.
Intramolecular forces: Secondary forces within the same macromolecular chain.
Life Cycle Assessment (LCA): Investigation and evaluation of the environmental impact of a
product or service. It is also referred to as an ecobalance analysis, cradle-to-grave analysis,
and life cycle analysis.
Linear: A continuous chain.
Macromolecule: A polymer. Large chained molecular structure.
Natural rubber (NR): Polyisoprene obtained form rubber plants; Hevea brasiliensis.
Nylon-66: A polyamide produced form the condensation of adipic acid and 1,6-
hexanediame.
Oligomer: Low molecular weight polymer with generally 2–10 repeat units.
Plasticizer: An additive that reduces intermolecular forces in polymers making it more
fl exible.
Polymer: A giant molecule, macromolecule, made up of multiple repeating units, where the
backbone is connected by covalent bonds.
Protein: A natural polyamide composed of many amino acid-derived repeat units.
Rayon: Regenerated cellulose in the form of fi laments.
Thermoplastic: A linear polymer that softens when heated.
Thermoset: A network polymer containing chemical cross-linking that does not soften when
heated.
Vital force concept: A hypothesis that stated that organic compounds can be produced only
by natural processes and not in the laboratory.
Vulcanization: Process where elastomers such as natural rubber are cross-linked by heating
with sulfur.

EXERCISES

1. Name six polymers that you encounter daily.
2. Why are there more chemists that work with polymers than with other areas?
3. Why are there so many outstanding polymer chemists alive today?
4. Which of the following are polymeric or contain polymers as major components?
(a) water, (b) wood, (c) meat, (d) cotton, (e) tires, and (f) paint
5. Name three inorganic polymers.
6. Name three synthetic polymers.
7. You look at the bottom of several containers. Identify what the bottles are made of from the fol-
lowing recycling codes found on their bottoms: (a) four with the letters LDPE, (b) six with the

letters PS, and (c) five with the letters PP.
8. Why is there a time delay between discovering a new polymer and commercializing it?
9. What are some advantages of polymers over metals?
10. It has been said that we are walking exhibitions of the importance of polymers. Explain.
11. Why are polymer-intense industries often located in the same geographical area?

12. Why might simple identification codes such as those employed for containers fail for objects
such as sneakers and tires?
13. How can (should) we become more environmentally responsible?

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