:: Plastics Applications
Plastics have made inroads virtually into every applications
- consumer, consumer durable and industrial.The versatility
has enabled their availability in every conceiveble forms
will economic advantages. One has to only look around to recognise
as to how plastics have become port of the everyday life usefully
and beneficially. The most common items we see :
Properties of Plastics
Plastics are derived from natural resources - petroleum oil
and natural gas. Plastic products have a fascinating, bewildering
and even bizarre range of properties. They can be rigid, as
well as flexible, they can provide retention (i.e. act as
barrier) as well as selective tailor-made permeation, they
are excellent insulators, but can also be made conductive.
They can have memory and can be even optically active; they
can be 'Instant' structural adhesives. They have high impact
strength; they can have high abrasion and scratch resistance.
The ease with which plastics can be processed into a variety
of articles of every day use is truly remarkable, and has
no parallel. Plastics are hallmark of conservation of energy
compared to steel and glass, and have additional advantage
Saving of our Forests
Natural Resources The wood used for furniture like tables
& chairs, doors & windows, packing of tea, mangoes,
grapes, apples etc, wooden crates for aerated water bottles,
are now being replaced by plastics. One estimate in 1944-45
indicates that if only 2% of the wooden boxes are changed
over to plastic we would save 1,200 ha of forests involving
1,10,000 trees. Wooden plate & frame-filters used in chemical
& allied industries can be completely replaced by plastic.
Cork used in a variety of applications like caps of aerated
water bottles can be replaced by plastic. The nursery for
forestry also benefit from plastic films.
Cotton and jute, in most applications can be replaced in
a very effective and profitable way by woven sacks made of
high density polyethylene or polypropylene. A lot of wastage
associated with use of packaging jute bags for cement, fertilizer,
pesticides, etc can be avoided by using waterproof plastic
Plastics in Agriculture
Plastics are used in a host of applications in the field
of agriculture e.g. plastic pipes in sprinkler irrigation
systems, plastic films in green houses, plastic nets in horticulture,
heavy duty flexible membrane lines for canal lining which
prevents water seepage- (It has been reported that 0.75 mm
PVC sheet provides a million times more permeation resistance
than 1m of clay as canal, dam and lake liner). Super absorbent
polymers in our arid, and semi-arid zones, all help substantially
to conserve water - a precious natural resource, to a great
Plastics for Fishing Industries
Fishing nets made of plastics have a long life. Even ropes
are made entirely of polypropylene or polyamide, and these
have a long life compared to other conventional ropes. FRP
boats have made a definite impact in our fishing industry.
Plastics in Desalination of Sea & Brackish water
Polymeric membranes have made major impact in recent years
in desalination of sea and brackish water. We now have large-scale
plants providing drinking water to the public. Here the net
consumption of energy, compared to multi-stage evaporator
based system is very lower, and hence saving of energy is
substantial. The availability of potable water in a number
of arid and semi-arid areas in Rajasthan, Gujarat, Tamil Nadu,
Andhra Pradesh, etc. is serious problem of society, and polymers'
contribution in tackling the issue is very great.
Plastics in Cryogenic Operations
Many cryogenic operations, for e.g. pure or enriched nitrogen
and oxygen, can now be based on polymeric membrane separations
or hybrid systems resulting in enormous power savings.
Enriched oxygen can be supplied for industrial purposes like
boilers, klins, furnaces etc. resulting in saving of substantial
energy. Even in hospitals enriched oxygen is being supplied
through membrane based modules.
Saving of Energy
Energy consumed on a functional basis, by a unit amount of
plastic, (polymers like LDPE/HDPE/PP/PS) which have densities
which is about one-seventh of that of steel, is very much
lower than that required for steel, and aluminum (aluminum
requires 13 times its weight in energy to produce 1 lb from
ore, steel six times). Plastic do not need frequent painting.
This is another saving. In many applications steel and aluminum
can be safely and profitably replaced by plastic at lower
cost and in saving Capital Investment, which we are always
in short supply.
Plastics (HDPE) pipes can be conveniently and advantageously
used for transportation of industrial gas, effluent pipelines
where liquids may be acidic and corrosive, and avoid the aberration
that we will have through the leakage of metal pipes.
Frictional losses in plastic pipes & fittings as a whole
and pipes for sprinkler irrigation systems are less, which
adds and to substantial saving of energy.
Replacement of asbestos and corrugated iron sheets by transparent/
translucent FRP sheets that provide daylight as well can result
in saving electricity.
Another welcome change is replacement of blades of fans (ceiling,
table & pedestal) with plastic based material, as it will
save substantial energy.
Polymeric additives make fuels and engines more efficient
in internal combustion engines and this helps in conserving
scarce petroleum products
According to American sources only 4% of United States energy
consumption is actually used to produce plastic raw materials
including feedstocks. It takes less energy to covert plastics
from a raw material into a finished product as compared to
other products. E.G.
- Plastic bags require only one-third of the energy required
to make similar paper bags.
- Foamed polystyrene containers take only 70% of the energy
to make paperboard containers.
- Fifty-three billion kilo watt-hours of electricity are
saved annually by improvements in major appliances. Energy
efficiency has been made possible by plastic applications.
- Plastics being strong, yet light weight, require less
material to make a certain package compared to other materials,
resulting in saving of energy, eg
||Plastic film wrappers now used for large diaper
packs need only 50% by volume, than previous packs.
||In the US 4 million students a day drink their milk
or juice in flexible pouches which reduce weight by
80% and volume by 70% as compared to traditional cartons,
reducing storage and trash disposal costs.
||Plastic grocery bags are lighter and create upto
80% less waste by volume than paper sacks.
- Because of durability, flexibility and increased life
span, plastic bottles etc can be reused several times, eg.
Packings for laundry products etc.
- The lightweight nature of plastics helps to reduce transportation
costs substantially. A truck that could carry only 5,00,000/-
paper grocery bags can transport 2.8 million plastic grocery
- Container breaches, denting and product loss on the package
lines during handling are substantially reduced because
of plastics' superior resistant to breakage and denting.
- Increased productivity by about 20-30% and reduced capital
expenditure to the extent of 50% can be achieved due to
highly superior manufacturing efficiency of plastics.
- Corrosion resistance will increase the life of major appliances
by about 40% resulting in substantial savings.
- The automotive industries choose plastics for their durability,
corrosion resistance, ease of colouring and finishing, resiliency,
energy efficiency and lightweight, which reduces handling
and transportation costs. Ease of fabrication and outstanding
thermal insulation, reducing energy consumption are the
prime considerations for major appliances manufactures for
- Aesthetic appearance, durability, ease of installation
and energy efficiency are the prime factors for the building
and construction industries to use plastic.
Some of the experiences of the US plastic industries as reported
are: Less waste - Plastics often help product manufactures
to do more with less material, which is known as 'resources
efficiency' or 'source reduction'. Source reduction is the
process by which a package or product is made using fewer
resources, creating less pollution and utilising fewer potentially
Manufacturers benefit by using less stuff, as their cost
is less and this helps to keep their consumer prices down.
This also results in resource conservation. The following
quotations will clarify certain other points:
"Plastic Engineers have helped manufacturers make production
using less material by lightening and thinning consumer product
packaging. Just 2 lbs plastics can deliver 1,000 ounces -
roughly 8 gallons - of beverage such as juice, soft drink,
milk or water. In its place we will need 3 lbs of aluminum
to bring home the same amount, 8 lbs of steel or 27 lbs of
"Plastics help make packaging more efficient, thereby
conserving resources. As a result, the consumer can buy larger,
economy size products (eg: laundry detergents). It also means
that it takes fewer trucks - and therefore less fuel - to
get the products to the consumer. For example: It takes seven
trucks to carry the same number of paper bags that fit in
one truck load of plastic bags".
"Reuse provides another significant way to conserve
resources. Plastic's durability allows many products and packaging
to be reused over and over again. Not surprisingly, in a 1977
Survey, Wirthlin Worldwide found that more than 80% of Americans
reuse plastic products and packaging for their homes. Plastics
are durable, making it a material of choice for commonly reusable
items, such as food storage containers and refillable sports
bottles. Reuse of plastics reduces trash disposal costs, and
extends landfill capacity. For example: as much as 40% of
certain plastic parts from damaged or discarded cars are repaired
and reused, reducing the amount of automotive components sent
to landfills. Laundry products are also being packed in reusable
plastic bottles and small refill packages of concentrated
products - helping to reduce packaging waste".
"Many US businesses have made the decision to receive
their supplies and ship their products in reusable plastic
containers (RPSCs) rather than single use corrugated boxes.
Over the past two years, the Ford Motor Company has eliminated
more than 150 million pounds of wood and carboard packaging
that would have gone to landfill, by asking its suppliers
to use returnable plastic shipping containers and plastic
rather than wood pallets. Returnable containers are also making
major inroads in the produce and meat packaging industries".
This topic has been dealt with in details in a separate paper.
Here is some more information: More than 80% of US households
make use of recycling program and 17,000 communities now collect
plastics for recycling. It is reported that 1.45 billion lbs
plastic bottles were recycled, in 1988, of which HDPE accounted
for 734 million lbs, and 710 million lbs of PET bottles including
580 million lbs of soft drink bottles.
Since 1999, the number of plastic recycling units has tripled,
with more than 1,700 businesses engaged in recycling post
consumer plastics. Approximately 1,300 commercially available
products are made with or packaged in post consumer recycled
plastics, including office supplies, park benches sweaters,
jeans, videocassettes, detergent bottles, toys etc.
The items that can be made with recycled plastic are growing.
Few examples. Recycled PET - deli and bakery trays, carpet,
clothing & textiles. Recycled HDPE - can become bottles
for laundry product, recycling bins, agriculture pipes, bags,
motor oil bottles, decking and marine pilings. Recycled Vinyl
- can become playground equipment, film and airbubble cushioning.
Recycled LDPE - can be used to manufacture bags, shrink films
and compost bins. Recycled PP - can be used in automobile
parts, carpets, battery casings, textiles, industrial fibers
Technical barriers currently limit use of recycled plastic
packaging coming in direct contact with food.
Advanced recycling: The term 'advanced recycling'
describes a family of plastic recycling process that yield
a variety of versatile end products. Feedstock recycling or
chemical recycling also refers to the same.
Recovery of Energy
Burning of municipal solid waste (MSW) or garbage is an important
way to conserve energy. The heat thus generated is used to
reduce steam and electricity, and is called 'Waste to Energy'
(WTE) facilities. According to American studies this process
can produce volume of MSW to be landfilled by as much as 90%.
Comparative table of the heat energy that can be obtained
by burning various MSW in special combustion chambers:
General MSW Plastic MSW Material btu/lb Material btu/lb Mixed
food waste 2,370 Mixed plastics 14,100 Mixed MSW 4,800 Polystyrene
17,800 Mixed paper 6,800 Polyethylene 19,900 News Print 7,950
In the United States there are now 103 energy recovery plants
operating spread over 32 states, generating enough electricity
to meet the power needs of 1.2 million houses and businesses.
Plastics in Packaging
Primary function of packaging is to help protect the quality
of goods - all marketable products, viz., fresh meat and vegetables
and prepared foods, industrial, equipment, sensitive electronics,
etc, during shipping, handling and marketing. Because of the
versatile nature of plastics they are most suitable for a
wide range of packaging applications. Plastics offer best
protection while using minimum resources, creating less wastage.
As compared to other conventional packaging materials, plastics
have minimum weight to volume ratio. Globally around 40%(which
may shortly go up to 60%) of polymers are used in packaging.
Polyethylene is the main polymer used for packaging. Plastic
being so versatile, each resin has attributes that makes it
best suited to a particular application. The following six
resins account for nearly all plastics used in packaging.
PET (polyethylene terephtalate) is a clear, tough polymer
with exceptional gas and moisture barrier properties. PET's
ability to contain carbon dioxide (carbonation) makes it ideal
for use in soft drink bottles.
HDPE (high density polyethylene) - Because of its excellent
protective barrier properties it is used for milk, juice,
and water containers. Its chemical resistance properties make
it ideal for containers for household chemicals and detergents.
Vinyl (polyvinyl chloride) provides excellent clarity, puncture
resistance and cling. As a film, vinyl can breathe just the
right amount, making it ideal for packing fresh meats that
require oxygen to ensure a bright red surface, while maintaining
good shelf life.
LDPE (low density polyethylene) offers clarity & flexibility
and is used to make bottles requiring flexibility. It is used
to make grocery bags, garbage bags, shrink and stretch film
making use of strength and toughness in film form of LDPE.
It is also used as coating for milk cartons.
PP (polypropylene) - Because of it high tensile strength
it is ideal for use in caps and lids that have to hold tightly
onto threaded openings. PP has high melting point, can be
hot-filled with products designed to cool in bottles, including
ketchup, and syrup. It is also used for products that need
to be incubated, such as yogurt.
PS (polystyrene) in its crystalline form is a colourless
plastic that can be clear and hard. It can be foamed to provide
exceptional insulation properties. Foamed or expanded polystyrene
(EPS) is used for making meat trays, egg cartons, coffee cups
etc and also used for packaging and protecting appliances,
electronic and other sensitive products.
Plastics help make packaging more efficient thereby conserving