Page 236 - Academic Press Encyclopedia of Physical Science and Technology 3rd Polymer

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Encyclopedia of Physical Science and Technology EN012F-600 July 26, 2001 11:16

Polymers, Recycling

Richard S. Stein
University of Massachusetts

I. Nonrenewable Resources
II. Means for Dealing with Plastic Waste
III. Recycling
IV. Overview

GLOSSARY tion of nonrenewable resources and (2) the environmen-
tal burden arising from their manufacture and disposal.
Alcoholysis Degradation accomplished by reaction with The volume of polymers used exceeds that of metals and
alcohol. is rapidly growing, particularly as the “third world” in-
Degradation The chemical conversion of a material to dustrializes. The driving forces for this trend are (1) the
lower molecular weight products. economics of their use as compared with alternate mate-
Entropy A measure of the degree of thermodynamic dis- rials, (2) their superior properties for many applications,
order of a system. and (3) their positive environmental impact resulting from
Hydrolysis Degradation accomplished by reaction with weight savings, superior insulation, and decreased pres-
water. sure on agricultural resources. The trend for increased use
Incineration The burning of material. appears inevitable, so consideration of how best to modify
Primary recycling Recycling involving physical chan- practices to accommodate this is essential.
ges without modification of the chemistry of the mate-
rial.
Pyrolysis Degradation accomplished through heat. I. NONRENEWABLE RESOURCES
Recycling The conversion of a waste product into a useful
new one. The concern about the effect of polymer use on consump-
Secondary recycling Recycling in which chemical chan- tion of nonrenewable resources may be excessive. The
ges are carried out, such as by degradation, pyrolysis, principal feed stock for polymer production is petroleum.
or hydrolysis. About 90% of petroleum is currently used as fuel, about
Trash-to-energy Incineration accomplished with energy 4–5% goes for petrochemical production, and only 2–3%
recovery. goes to polymer manufacture. The amount of petroleum
saved through the use of polymers for weight reduction in
automobiles and aircraft and for reduced heating oil con-
THE RAPID GROWTH in the use of polymers has re- sumption due to better insulation is probably greater than
sulted in concern about (1) their influence on the consump- that needed to produce the polymers. Such would occur as

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