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July 31, 2010

Plastics

Toys, compact disc, plastic bags, Tupperware do u have any ideas what materials is these items made of? Most people don’t know but they don’t even bother to do. These items sometimes will be immediately disposed without knowing the side effects or the pollution it may cause to the environment. These items are made out of plastics.

These plastics can be made from cellulose from plant oil. And most commonly it is made from petroleum same as what we use to fuel our car. The petroleum we used to fuel our car is formed in all organic matters which are buried deep inside our Earth, after a long period of time it will eventually become crude oil which is also know as petroleum. Not 100% of these petroleum are use to fuel our car, 16% of the petroleum will be process to make plastics. Additives will also be added to form plastics.

The technological route from fuel to plastic products has a numerous way but here will be an example for it. Petroleum was drilled out and transport to refinery. This petroleum will then be refined into ethane propane and also hundreds of petrochemical substances including the fuel for our car. The ethane and propane are then break into ethylene and propylene in a reactor by using high temperature furnaces. After that, a catalyst will be added with ethylene and propylene in a reactor and produce a powder like polymer which resembles laundry detergent. Then this fluff will be combined with additives in a continuous blender. Then this polymer will fed to an extruder where it is melted. Melted plastic is cooled and cut into small pellets by a pelletizer. Then these pellets will then shipped out to customers who order. The customers will eventually manufacture the plastic products by using processes such as extrusion, injection molding, blow molding and etc.

Government, college and also corporation nowadays are trying to change this petroleum-based plastics into biodegradable based. But there is a barrier which stop them from doing so which is the cost. The biobased major materials will be the plant oil but with the rising of the plant oil prices , it will seems hard for them to changed it immediately. Water bottles, food containers, water pipe most of these was made from petroleum based plastics therefore, it will be very hard for them to change it.

When people had used up these things they decide to dispose it. But all these petroleum-based plastics are hard to decay and estimated to have a 500 years lifespan which will become garbage which end up in the landfill for centuries. This is because they are made from non-renewable petrochemicals, styrene and a key ingredient of polymer which is carcinogen which are known as a hazardous substance.

Plastic can release harmful and cancerous chemical that is why nowadays a lot of country had started to banned plastic. For an example, plastic bottle made of polycarbonate can release a chemical called Bisphenol A (BPA), this chemical also known as a kind of environmental estrogen. This chemical can be released when it was exposed to hot boiling water no matter the plastic bottle is new or used. This chemical is harmful is because it can disrupt the endocrine system of a man.

Figure 1 Bisphenol A

Therefore, plastics are really harmful to us and also the environment. We do hope that there will be a better future for out kids so think twice before using a plastics bag because there is always a second choice.

1 comments:

Alice Phua said...

Talking about plastics....this reminds me about supermarkets/hypermarkets nowadays going for those biodegradable plastic bags. I realize the downside to biodegradable ones is that when they do biodgrade, they crumble into tiny pieces when you store it for too long in a place. not only does the tiny bits dirty and mess up the place, but it looks hazardous when accidentally inhaled if you happen to whif the thing and all the tiny bits start flying and floating in air.

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