Page 729 - Carrahers_Polymer_Chemistry,_Eighth_Edition

692 Carraher’s Polymer Chemistry

11. Some of the important properties are the ability to tailor-make structures, surface control,

strength, flexibility, rigidity, inertness/reactivity, light weight, ease of fabrication, ability to
achieve a high degree of purity, lack of and because of their water solubility/compatability,
bioerodablity, and the ability of some of them to withstand long-term exposure to the human
body—a truly hostile environment.
12. Almost all denture bases are made of methacrylic (acrylic) resins that give good fit and a nat-

ural appearance.
13. Nylon, because tissue reaction is minimal. Nylon is strong and cuts on the leg often are exposed
to high stresses as the person heals. It has good tensile strength and little elongation change. It
offers good knot security and low tissue drag.
14. Poly(ethylene oxide), copolymer containing about 50% ethylene and about 50% acrylic acid
units, and poly(vinyl alcohol).
15. Only PP.
16. PVC decomposed giving the toxic gas hydrogen chloride when burned.
17. Yes. There is a sufficient proportion of the polymer that hydrogen bond to water, allowing it to

be water soluble.
18. Its cost is too high and it does not have good dimensional stability meaning it is not easily cut,
drilled, or sawed.
19. Polymers are light weight, can be designed to be permanent or short lived in the body, can be
designed to become part of the bodie’s complex structure, high strength, varying requirements
needed in biomaterials that can be incorporated into a polymer structure, and so on.
20. Probably a number of reasons can be cited, including general inertness and a tendency toward
being slick.
21. There are both political and environmental reasons. Green materials are in some ways relatively
rapidly regenerating lowering our dependence on less-rapidly regenerated petroleum resources.
They should also more easily be returned to the earth renewing the nutrients needed to sustain
the earth. Further, they should require less nonsolar energy and should offer less pollution.
Increase in petroleum cost and recognition that the petroleum reserves are limited, and so on.
22. Again, there are political and environmental reasons. Many things drive this move. For instance,
industry wants to capture popular press to have their products included under the umbrella of
green materials. But, also industry recognizes the need to make products that do not have a
negative impact on the environment and is working to make materials that perform well and are
economically and environmentally better, and so on.
23. PLA, PHB, and ricinoleic acid.

9/14/2010 3:44:24 PM
K10478.indb 692 9/14/2010 3:44:24 PM
K10478.indb 692