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Polymers and the environment:

Polymers are widely known as plastics among people. However, the big image on plastics for the most is
not a positive one, probably due to some of the environmental issues that cased by various polymers. It
should be noted that not all polymers have a negative environmental impact. Thus, it would be better to have
a general understanding of polymers, their uses, advantages and disadvantages, and the modifications that
are possible to improve the properties of the polymers for the better.
With the advancements of science, a variety of
polymers are emerging everyday. Scientists are
working relentlessly to improve the properties of
existing polymers as well as to find new variety of
polymers. Articles made from synthetic polymers
can be found in every area of life. For example,
polyvinyl chloride (PVC) is used in toys, pipes,
fittings, sidings, wall and floor coverings, cable
coatings, medical devices etc. One of the widely
used consumers plastic is polyethylene
terephthalate (PET). PET is used mostly to make
bottles, food packaging containers etc. Polylactide,
a biodegradable synthetic polymer, derived from
renewable resource corn, has found wide variety of
applications in products including disposable
grocery bags, cutlery, as well as in apparel and
clothing. Details of most of these polymers are given
in other sections of this site.
Recycling of plastics:

Most plastics can be recycled to make useful materials after
their intended use. To make it easier to separate and identify
various articles made from different polymers, universal recycling
coding system has been developed by the Society of Plastic
Industry. According to the system, products are coded as
follows:

Number
1 for PET,
2 for High density Polyethylene((HDPE),
3 for polyvinyl chloride (PVC), 4 for Low Density Polyethylene
(LDPE),
5 for polypropylene (5),
6 for polystyrene (6),
and 7 for other polymers such as acrylic, polycarbonate, nylon
etc.

To complete the code, these numbers are enclosed by a
rounded triangle made from arrows that cycle clockwise. More
often an acronym that represents the plastic also is placed
below the code. Among the various different plastics used in the
world, only PET, HDPE and PS are the more-often recycled
plastic. However, arguments are still going on the worthiness of
recycling, as it emits more CO2 to the environment than when
burying in landfills. Thus, with increasing environmental issues
due to stockpiling plastic wastes in landfills, people around the
world are paying more attention to reduce the production and
usage of non-degradable plastics. In addition to recycling, reuse
of plastic bags, using other types of containers made from
environmentally friendly materials such as clay and ceramic,
metals should be encouraged in the general public.
In addition, scientists around the world are finding ways to make
environmentally friendly plastics that can compete with
petroleum based polymers. Special attention has given to use
renewable resource agricultural based raw materials to make
polymers which usually degrade in landfills without eliminating
toxic materials to the environment. One of the mostly used raw
materials is corn, beet and other agricultural sugars which by
fermentation could convert to make the starting material for the
polymer. In addition, scientists are using bacteria which could
grow the polymer in themselves.