Transcript Document

Introduction
Plastics 001
Plastics
Introduction to Materials
www.recyclingghk.com
Introduction
Plastics 001
If you look around, you will probably be able to identify many different types of
materials
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Wood
Metal
Stone
Glass
Plastic
Image by SantiMB. Copyright Creative Commons.
How much do you know about these materials that surround you?
Most of these materials have been around for thousands of years, but plastics
as we know them today have only been around for a couple hundred
years.
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Why do we use plastic?
1. Versatile
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Can easily be formed into very complex shapes
2. Relatively Inexpensive
3. Many processes are easily automated
4. High strength to weight ratio
5. Can quickly produce a lot of parts
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Why do we use plastic?
6. Good insulation properties
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Thermal
Electrical
7. Corrosion resistance
8. Can be made transparent or easily colored
9. Capable of being foamed
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Lightweight
Flexible
Many of the products used today would not
be possible without plastics.
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When you hear the word PLASTIC, what comes to
mind?
What is a ‘PLASTIC’?
What is a ‘POLYMER’?
How long have plastics been around?
How much plastic is used each year?
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When you hear the word PLASTIC, what comes to mind?
According to Dictionary.com a plastic can be defined as
Any of a group of synthetic or natural organic materials that may be
shaped when soft and then hardened, including many types of
resins, resinoids, polymers, cellulose derivatives, casein materials,
and proteins: used in place of other materials, as glass, wood, and
metals, in construction and decoration, for making many articles, as
coatings, and, drawn into filaments, for weaving. They are often
known by trademark names, as Bakelite, Vinylite, or Lucite.
http://dictionary.reference.com/browse/plastic
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The definition of a polymer is:
Polymer - Any of numerous natural and synthetic compounds of usually
high molecular weight consisting of up to millions of repeated
linked units, each a relatively light and simple molecule.
Most of the materials we refer to as plastics are technically polymers.
http://dictionary.reference.com/browse/polymers
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Basically a plastic is a material that you can shape when it is soft and it
will then harden.
It can be a naturally occurring
material like clay.
It can be a synthetic material
like Polyethylene.
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When we think of plastics today, we are primarily talking about
polymers or a group of synthetic organic compounds, that are heated
and shaped to make items ranging from children’s toys to automotive
components to high tolerance medical parts.
An organic compound is a material that is composed of primarily Carbon
(C).
Today’s plastics are mostly created from oil and natural gas – but some
are created from agricultural sources like corn.
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The word POLYMER comes from the Greek language and basically
means many ‘mers’
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A ‘mer’ is a unit
Polyethylene means many ‘ethylenes’
Think of it like each unit is a bead and the final
molecule is the string of beads – only the string
usually has several thousand beads
Ethylene
Polyethylene
H H
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C= C
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H H
H HHHHHHHHHHHHH
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[-C-C-C-C-C-C-C-C-C-C-C-C-C-C-]
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H HHHHHHHHHHHHH
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Molecular Weight
The molecular weight of a polymer depends on the length of the chain
(The number of ‘mers’ (beads) times the weight of the ‘mer’)
The length of the chain will effect the properties or the molecule and the state or
phase of the material
• 2 ethylene ‘mers’ = butane (a gas found in lighters)
• 4 ethylene ‘mers’ = octane (gasoline)
• 10-20 ethylene ‘mers’ = greases or oils
• 200-300 = waxes
• 10,000 + = polyethylene
Each polyethylene ‘mer’ has a molecular
A mole is a unit of measure
weight of 28 grams/mole, so a molecular
for atoms and molecules
chain of polyethylene 10,000 ‘mers’ long
would have a molecular weight of 280,000 grams/mole
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Structure
The structure of polymer materials leads to their unique properties as
well as some of their disadvantages.
–Dimensional instability
–Some absorb moisture
–Many are flammable
–Some are attacked or dissolved by certain chemicals
–Many take a long time to degrade when disposed of
Different material families will have different disadvantages, which is
why it is very important to choose the right material for the right
application.
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History
Natural polymers have been around longer than we have.
Natural rubbers, cellulose, spider webs, and animal horns are all
examples of natural polymers.
Man has worked with natural polymers to
create objects for a long, long time.
It wasn’t until the mid 1800’s that man began to modify natural
polymers to make them easier to process and increase their
usefulness.
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History
Much of the development/discovery of plastics
has either been in the attempt to replace other
materials or through accidental discovery.
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Much of the development of PVC (Vinyl) was
in an attempt to replace rubber
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Nylon development was spurred on by the need to
replace silk in parachutes and ropes
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Teflon (Polytetrafluoroethylene) was discovered
accidentally in a DuPont Lab when working on
alternative refrigerants.
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Celluloid was developed in response to a need to
replace ivory in billiard balls.
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The ages of man are listed as;
Stone Age – man made primitive tools and weapons from stone.
Bronze Age – man began to smelt copper and tin to make items
Iron Age – man began to work iron
The late 20th century and on could very well be named the Plastic Age.
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Many of the technological developments of the past 50 years
would not have been possible without the discovery and
development of plastic materials
Plastics have allowed for
the miniaturization of
many of today’s
common devices:
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Laptops
Cell phones
Ipods
Etc.
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Plastics are highly used in almost every industry
Automotive
Medical
Construction
Packaging
Consumer goods
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Volume
In 2006 there were 113.2 billion pounds of plastic produced
worldwide.
Making products out of plastic saves energy not only in the production
of the items, but also in the transportation of those items.
Because of the incredible volume of plastics used in today’s society,
many activist and political groups are concerned with the recyclability
of plastic materials.
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Recycling
Plastic materials do not decompose quickly in a landfill
environment.
– The lack of oxygen and sunlight slows the decomposition
process.
This is the reasoning behind two main initiatives in the plastics
industry
1. Recycling
2. The development of
degradable polymers
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Recycling
On average we recycle around 27% of the plastic products that are
produced with some materials being as high as 60%
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Recycling
Common products made with recycled materials:
Carpet
Rope
Flower Pots
Trash Cans
Drainage Pipes
Grocery Bags
Plastic Lumber
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Biodegradable materials
The other option to recycling is the development of degradable
materials.
The development of these materials is also driven due to the rising
cost of oil and natural gas.
The most prominent material in this area is probably Polylactic Acid
which is processed from corn.
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Material Families
Of the 113.2 billion pounds of plastic materials produced in 2006; the
major material ‘families’ are broken down in the following distribution.
Polyethylene
9 Million Metric Tons
Polypropylene
8.4 Million Metric Tons
Poly Vinyl Chloride (PVC)
7.3 Million Metric Tons
Polycarbonate
3 Million Metric Tons
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Questions?
Plastics 001