Q: What is the formal definition of Polystyrene?
Polystyrene, sometimes abbreviated PS, is an aromatic polymer made from the aromatic monomer
styrene, a liquid hydrocarbon that is commercially manufactured from petroleum
by the chemical industry. Polystyrene is a thermoplastic substance, normally existing in solid state at
room temperature, but melting if heated (for moulding or extrusion), and becoming solid again
when cooling off. Polystyrene is one of the most widely used kinds of plastic.
Pure solid polystyrene is a colourless, hard plastic with limited flexibility. It can be cast into moulds
with fine detail, for example yogurt cups, plastic cutlery and CD and DVD cases. Polystyrene can be
transparent or can be made to take on various colours. Products made from foamed polystyrene are
nearly everywhere, for example packing materials, insulation, and foam beverage cups.
Q: What is styrene?
Styrene is a clear, colourless liquid that is derived from petroleum and natural gas by-products, but
which also occurs naturally in food such as coffee, strawberries and cinnamon. Styrene helps create
plastic materials used in thousands of remarkably strong, flexible, and lightweight products, which
represent a vital part of our health and wellbeing.
It's used in everything from food containers and packaging materials to cars, boats, and computers.
The styrene used in these products is synthetically manufactured in petrochemical plants.
Q: What are CFC's?
CFC's, or chlorofluorocarbons, is commercially, the most important CFC's that is derivatives of
methane and ethane. CFC's were first introduced in the 1930s as safe replacements for refrigerants
such as sulphur dioxide, ammonia, chloroform, and carbon tetrachloride. These uses eventually
resulted in large emissions of CFC's into the atmosphere.
Because of their low chemical reactivity, CFC's typically have long atmospheric residence times, and
as a consequence are distributed globally. However, when CFC's reach the stratosphere they break
down to release chlorine atoms. The chlorine atoms then react with
stratospheric ozone, breaking it down into oxygen.
As ozone absorbs much of the sun's ultraviolet radiation, decreased stratosphere ozone levels could
lead to increased ground-level ultraviolet radiation. This could adversely affect crop growth, and also
lead to increases in cataracts and non-melanoma skin cancer.
CFC's are therefore now banned because they are the cause of the holes that grew in the ozone
layers over the planets polar regions.
The banning of CFC's has lead to research to identify other chemicals that can be used in
the same applications but without the same environmental concerns.
Q: Is it safe to heat food in a plastic container in the microwave?
Rumours about the safety of using Polystyrene (also known as the brand name Styrofoam) in
microwaves have circulated, stating that plastics form dioxins when heated in the microwave. This is
completely untrue. For one thing, there is no reason for plastic containers to contain dioxin unless
the purpose is to store dioxin and, important to note, dioxins typically form at temperatures above
370°C.
Contrary to popular belief, some Expanded Polystyrene (EPS) and other polystyrene containers, such
as salad or yogurt containers, can safely be used in the microwave.
Just follow the same rule you follow for other plastic containers: Check the label.
Q: What is all the talk about ‘landfill space’?
For hundreds of years, people have used garbage dumps to get rid of their trash. Yesterday’s
garbage dump was nothing more than a pit or field just outside of town where people left their
garbage. Today, we still bury our garbage, although not in the open dumps of yesterday.
Most of our garbage is hauled off in garbage trucks and packed into sanitary landfills—making land
filling.
The problem is that we, in South Africa, have a waste problem and we are running out of landfill
(dumping) space at an alarming rate. Just in Cape Town, they dump a total of 6 000 tons of waste
every day. To give you a better idea of how much space 6 000 tons of waste would take up, if you
have a normal 3m x 2m room in your house, and you fill it up with waste all the way to the roof, you
will have one ton of waste.
Q: Give me 4 good reasons why I should recycle?
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We only have enough landfill space for the next 3 years and by the time that the last landfill
site closes down; we would be building mountains of waste equivalent to 6 000 rooms per
day.
One of the major contributors to greenhouse gasses (the gas in the atmosphere that
prevents radiation from the earth to escape that in turn causes Global Warming) is Methane
Gasses. Methane Gasses are mostly released from old landfill sites. Can you see how
recycling will prevent Global Warming?
The materials that you recycle will go back into the production streams and it will save huge
amounts of energy and raw materials.
It is the right thing to do!
Q: What products are made from recycled Polystyrene?
Polystyrene is not only versatile as a product, but also versatile in the recycling thereof. Products
made from recycled Polystyrene include:
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Coat hangers
Seedling trays
Curtain rods, finials and holdbacks
Cornices and skirtings
Outdoor furniture
Poles and decking
Questions and Answers
What is styrene?
Styrene is a liquid that is derived from petroleum and natural gas by-products, but which also occurs
naturally. Styrene helps create plastic materials used in thousands of remarkably strong, flexible, and
lightweight products that represent a vital part of our health and wellbeing. It's used in everything
from food containers and packaging materials to cars, boats, and computers. The styrene used in
these products is synthetically manufactured in petrochemical plants. However, styrene also occurs
in the environment and is a natural component of many common foods, such as coffee, strawberries
and cinnamon. Some people confuse styrene, which is a liquid, with polystyrene, which is a solid
plastic made from polymerised styrene. Styrene and polystyrene are fundamentally different.
Polystyrene is inert, and has no smell of styrene, therefore polystyrene often is used in applications
where hygiene is important, such as health care and food service products.
Is styrene present in polystyrene?
Very small amounts of styrene monomer that was not converted into polystyrene during processing
do remain in finished polystyrene products. Numerous studies and investigations have been carried
out to determine if there is a safety concern regarding the amounts of styrene that remain in
polystyrene resins. The results of these studies indicate that polystyrene is safe for use in foodcontact products. Styrene is approved for use as a starting material for the production of polystyrene
food and beverage packaging by regulatory agencies worldwide. The European Food Safety
Authority has not assigned a so called 'Specific Migration Limit' to styrene. Many surveys made from
e.g. the UK Ministry of Agriculture, Food and Fisheries (MAFF) in the late 90-ies gave complying
values for food packaged in polystyrene. This survey was repeated in 2003 and gave again complying
values.
For more information see link: www.food.gov.uk/news/newsarchive
Do I come into contact with styrene?
Styrene is a natural component of some foods, and is present in small amounts in foods such as
cinnamon, beef, coffee beans, peanuts, wheat, oats, strawberries, and peaches. Most people are
exposed to styrene in tiny amounts that may be present naturally in the diet, air (styrene is a
component of cigarette smoke, gasoline and fuel exhausts, and, in trace quantities, as a result of
using food-service packaging). Scientific studies have shown that the very small amount of styrene
that people may be exposed to from packaging is about the same amount as comes from naturallyoccurring styrene in foods. These studies have also shown that these levels of exposure are safe and
should not be a cause for concern.
Is styrene harmful to my health?
Styrene is harmless in the very small amounts most people might normally encounter in air or food.
The general public is very unlikely to encounter high levels of styrene. In fact, styrene is approved by
the US Food and Drug Administration as a food additive. Major studies in Japan, United States and
Europe have shown that even at exaggerated levels of exposure, the oligomers (combination of two
or three styrene molecules) that can migrate from polystyrene did not show an estrogenic effect.
For those directly working with the product (i.e. professional users, the people involved in the
conversion of styrene into the final items we use in the everyday life), the relevant safety measures
are provided by means of a Safety Data Sheet. Governments and Industry have set safe exposure
limits for professional workers.
As part of a continuing effort to protect health and the environment, the European Union and the
U.S. Environmental Protection Agency are both currently conducting formal reviews that will provide
safety assessments of the scientific data on styrene.
What about the odour of styrene?
Styrene's distinctive odour can be detected even when styrene is present at extremely
l low levels - levels that are many, many times below any level that may result in a possible
health effect.
Is there a concern about a risk of cancer?
Styrene is currently under European risk assessment to investigate its impact on the environment
and human health. The general population incurs no detectable risk resulting from styrene exposure.
Existing work place exposure limits represent a satisfactory precautionary measure to protect
styrene-exposed workers