A Short History Of Plastic

Some things you need to know about plastic are

 

 

plastic is made from oil

 Crude oil and natural gas are refined into ethane, propane, hundreds of other petrochemical products and, of course, fuel for your car. 

 Ethane and propane are “cracked” into ethylene and propylenewhich are  combined with additives, mixed up and melted. The melted plastic is then cut into pellets called nurdles.  These are shipped to customers who then  manufacture plastic products by using processes such as extrusion, injection molding, blow molding, etc.

Chemicals in Plastic

There are numerous chemicals used in the plastic making process. 

Plastic Properties

Plastic is waterproof light weight and strong

plastic is rot proof – it does not biodegrade it degrades

biodegrading refers to the breaking down of organic substances by natural means. Any plant-based, animal-based, or natural mineral-based product has the capability to biodegrade

Here’s how long it takes for some commonly used products to biodegrade, when they are scattered about as litter:

Cotton rags ~ 1-5 months
Paper ~ 2-5 months
Orange peel ~6 months
Tin cans ~ 50 to 100 years
Aluminium cans ~80 to 100 years

Degrade – referes to the process of breaking up by mechanical means.

Plastic does not biodegrade – because it is a combination of elements extracted from crude oil then re mixed up by men in white coats.

Because these combinations are man made they are unknown to nature. Consequently there is no natural system to break them down.

It doesn’t biodegrade but it does rip, tear and break up into smaller pieces. This process is called degrading. Plastic continues to break down until it is invisible plastic dust.

Does plastic rot?

heres all kinds of talk about the biodegradabilitiy or otherwise of plastic. Generally speaking plastic does not biodegrade but degrades

 Slate have an interesting article on the subject.

Oil to Plastic

The information on this sheet has been taken from the following website

“http://www.reachoutmichigan.org/funexperiments/quick/plastic.html

In 1951, two young research chemists for Phillips Petroleum Company in Bartlesville, Okla., made discoveries that revolutionized the plastics world. Today, the plastics they discovered—polypropylene and polyethylene—are used to produce the vast majority of the thousands of plastics products all over the world.
The source for today’s wide variety of plastics? Petroleum. 

The technological road from oil field to finished plastic product has numerous fascinating side trips. Here’s the route taken in the petroleum-to-plastics process: 

1. Petroleum is drilled and transported to a refinery. 

2. Crude oil and natural gas are refined into ethane, propane, hundreds of other petrochemical products and, of course, fuel for your car. 
3. Ethane and propane are “cracked” into ethylene and propylene, using high-temperature furnaces
4. Catalyst is combined with ethylene or propylene in a reactor, resulting in “fluff,” a powdered material (polymer) resembling laundry detergent. 
5. Fluff is combined with additives in a continuous blender
6. Polymer is fed to an extruder where it is melted. 
7. Melted plastic is cooled then fed to a pelletizer that cuts the product into small pellets.   
8. Pellets are shipped to customers. 
9. Customers manufacture plastic products by using processes such as extrusion, injection molding, blow molding, etc.

How plastic is made

Oil is sold between countries in quantities called barrels. (The same measurement is used to sell whisky.)

One barrel of oil is the same as:

159 litres (about 80 large fizzy drink bottle)

35 gallons (enough to fit in the petrol tanks of about 4 cars)

280 pints (a lot of bottles of milk)

The weight of a barrel depends on where the oil comes from. However, there are about 8 barrels in a tonne.

You could fit nearly 2 million barrels of oil into a football stadium – or one and a half tankers. This is how much oil we use in the UK every day.

In 2003 a barrel of crude oil cost about $28 – about £17. 

Where do products come out of a still?

http://resources.schoolscience.co.uk/ExxonMobil/knowl/2/2index.htm?levelft.html  

 

Crude oil is a mixture of lots of different oily substances. Luckily for us, they all boil at different temperatures. So we can separate them in a distillation tower (or still). The thinner, runny ones have lower boiling points. They get all the way to the top of the tower before they condense. It is cooler at the top of the tower.The thicker, sticky substances have higher boiling points. They don’t get far up the still

http://resources.schoolscience.co.uk/Exxonmobil/infobank/4/2index.htm?oilcost.html

 

Flow diagram of oil refinary taken from

Wickipediahttp://upload.wikimedia.org/wikipedia/commons/6/60/RefineryFlow.png 

Why Plastic Degrades Not Biodegrades.

Biodegrading, the breaking down of organic substances by natural means, happens all the time in nature. We live, we die, we rot and so we feed the next generation – that’s life. Even if you are a rock. All plant-based, animal-based, or natural mineral-based substances will over time biodegrade.

In its natural state raw crude oil will biodegrade but man-made petrochemical compounds made from oil, such as plastic, will not. Why not – because plastic is a combination of elements extracted form rude oil then re mixed up by men in white coats. Because these combinations are man made they are unknown to nature. Consequently there is no natural system to break them down. The enzymes and the micro organisms responsible for breaking down organic materials that occur naturally such as plants, dead animals, rocks and minerals, don’t recognise them.

This means that plastic products are pretty much indestructible in a biodegradable sense at least. Which is in many ways fantastic and plastic is indeed a wonder product. But there is a downside. What happens to plastic in the environment?

DEGRADING
As time passes plastic will eventually break down into smaller and smaller pieces. This is a mechanical process involving mechanical actions such as ripping splitting and falling apart. Plastic merely breaks up. No matter how small the pieces they are still and always will be plastic. they are not absorbed into or changed by natural processes.

Dr Richard Thompson of the University of Plymouth has identified plastic particles thinner than the diameter of a human hair. But while they cant be seen those pieces are still there and are still plastic. They are not be absorbed into the natural system they just float around within it. He estimates that there are 100,000 particles of plastic per sq km of sea bed and 300,000 items of plastic per sq km of sea surface. Barnacle, lugworm and amphipods hoover up the tiny plastic particles as they feed. Who eats the amphipods – the little fishes and who eats the little fishes? That’s you that is with your fish, chips and microscopic plastic particles.

Why Leaves Rot

Biodegrade is one of those terms bandied about when talking about nature and natural processes that everyone assumes you know the meaning of. Not me. I mean I kind of knew but wouldn’t want to be questioned closely. So what does biodegrade mean? If the words grandmother and eggs spring to mind skip the next bit, if you messed around in biology putting frogspawn in your mates pencil case read on.

Biodegrade refers to the breaking down of organic substances by natural means. Natural means, means the breaking down is done by naturally occurring entities – things that are made in the body such as enzymes ( clever things that enable chemical break downs) or micro organisms that inhabit the teeny tiny world ( bacteria, fungi and exceptionally small plants and animals ). Any plant-based, animal-based, or natural mineral-based product has the capability to biodegrade

The key point is, is that the process of biodegradation is an integral part of the natural cycle. This process could be called rotting or decomposing or other nasty sounding things and yes it can be smelly but it is the very basis of life. Because as natural materials break down they release all kinds of nutrients that are used to feed other living organisms. Orange rind becomes compost which releases nutrients the orange tree can utilize. The tree feeds and so has the energy to make fruit which we eat discarding the peel which then biodegrades into compost – feeding many other creatures along the way including worms. Its a kind of magic

Here’s how long it takes for some commonly used products to biodegrade, when they are scattered about as litter:

Cotton rags ~ 1-5 months

Paper ~ 2-5 months
Natural fibre rope ~ 3-14 months
Orange peel ~6 months
Wool socks ~1 to 5 years
Leather shoes ~25 to 40 years
Tin cans ~ 50 to 100 years
Aluminium cans ~80 to 100 years
Glass bottles ~1 million years

For more information tryhttp://www.wisegeek.com/what-are-enzymes.htm

http://en.wikipedia.org/wiki/Microorganism