Year 11 Chemistry
Introduction
Throughout these thousands of years, mankind have been using natural
plastics. These plastics come from natural resins of nature. The use of
plastics date back to when the Egyptians soaked burial wrappings in natural
resins to help preserve their dead, and people had also used animals horns
and shell for centuries to make spoons and combs.

The development of plastics was invented in about 1860, when Phelan and
Collander, a U.S. pool and billiard ball company, was offering a prize of
$10,000 to the person who could design the best substitute for natural
ivory. Throughout those entrants, a person name John Wesley Hyatt although
wasn’t the winner, but had developed a cellulose derivative for that
contest. Later on, his product was named Celluloid, which resulted in a
successful organization of product, where companies had began using his
product in order to produce a range of items.

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Later on in 1920, a German scientist name Hermann Staudinger had ordered
out a advance information of plastic materials. He stated that plastic were
made up of very large molecules held together by a strong force. From his
theory, in the 1920’s and 1930’s plastic research had raised, manufacturing
new plastic every year. Some of these include nylon, methyl methacrylate,
Plexiglas, and polytetrafluoroethylene.

Every since, new types of plastic have been produced, with each their very
own characteristics and purpose of use.


Plastic buckets
Types of Plastics
Plastics are believably made of natural/synthetic materials. Plastics are
produced by chemically modified natural substance or either is synthesized
from organic raw materials. Due to the different physical characteristics,
plastics are positioned into either thermosets, elastomers or
thermoplastics. These group differ through the difference in molecular
structure, having plastic falling into their groups with different thermal
behaviour.

Thermosets- Thermosets have a very tight scaled branched molecular
structure making the material very hard. After the process of shaping the
desire shape, the plastic will no longer allow any reshaping, even if the
material is again heated. The only method to reshaping the material is
performed by machinery. Thermoset plastic are used for making items like;
light switches, the handle of a kettle, plastic bins, and the knob of a
saucepan.

Elastomers- Elastomers have a more looser mesh molecular structure then
thermosets, giving the plastic the ability to stretch to a degree. However,
in terms of shaping the plastic, it is exactly like thermoset plastic where
the plastic no longer allow any reshaping after the final process. It is
used for vehicle tires.

Thermoplastics- Thermoplastic are plastic in which can have a linear or
branched molecular structure. At room temperature it is flexible, but once
reaching a limitation of temperature is begins to melt into a liquid. This
type of plastic are used for packaging and shopping nags.

pic
The molecular structure of thermoset plastic
pic
The molecular structure of elastomers
pic
The molecular structures (branch and linear) of the two kind of
thermoplastics
In the world, there are a huge variety of different plastics, each possess
with their own useful properties and characteristics. Generally, all
plastics are lighter then many other materials of comparable strengths,
where unlike metal plastic doesn’t rust. Most plastics can be produced in
almost any colour as well can be manufactured to an extent where it is
identical to glass, having to be translucent, and opaque.

Some plastic polymers are very hard and rigid like bowling balls, helmets,
while others are soft and flexible like foam mattresses. Some polymers are
resistant to heat, while there are others are easy to melt. Some polymer
also has the ability to be molded over and over again, while there are many
that stay in formation. These characteristics all depend on the molecular
structure of the plastics.

Nowadays, with the use of advance technology and intelligence, chemist can
produce plastic in order to suit specific needs by controlling the polymers
properties. This include the determination of size of the molecule and the
structure, either having it be branched or linear.

The reason for the different molecular structure of different types of
plastics is to suit our requirements. For example if we were to designing a
outdoors water tank, we require a suitable plastic in which has ability to
withstand heat, durable, flexible, and long lasting.

The Use of plastics
Since the development of plastic earlier this century, it has become one of
the most popular material used. The uses of plastics are essentially
limitless. Plastic is found almost everywhere. Although for these many past
years of producing and usage, we are not aware of how we are harming the
world. Today plastic is used to make or wrap around many of the items

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