Monday, 16 November 2009

Plastics: Ask the Experts

Visitors to Plastics: A valuable resource posed some interesting questions to the Manchester Polymer Group. Here are the questions and some answers:

Vimto Vicky says heya and smile

Becky advises us to try and stop global warming by not using as many aerosols and to hang our washing outside to dry (if is not raining)
Very useful comments Becky. However it is good to note that ozone depletion chemicals previously used in aerosols are now no longer used under an international agreement.

Am from Stockport “Why haven’t all new houses/builds got solar panels/cells”
Another good question. There may be cost and public acceptance issues that need to be addressed.

Daniel Lewis from Chorlton “Do you use solar power, hydropower, geothermal power or wind power more”
Assuming that your question relates to plastics production and recycling operations, hydropower is used in those countries that have the geographical capability and have invested in this technology. As far as we are aware solar and wind power can also be used for less power demanding operations. Investment is also starting in an Energy from Waste plant in Cheshire.

Annie “Why do things melt”
Melting is the result of enough heat energy being transferred into a material, such as chocolate, to turn it into a liquid. So when you eat chocolate, it melts in your mouth because the temperature of your mouth is higher than the temperature at which chocolate melts.

Rebecca from Chorlton “Where do plastics come from”
Hannah from Chorlton “Why is plastic such a common material”
Plastics come from crude oil or gas after refining and account for 4% of the fossil fuel resources. They appear to be in common use because they are very versatile and can be used in many different ways.

Isobel “Why cannot we recycle all plastic”
Good question. It is possible to recycle all thermoplastic type materials (but not the thermosets such as light switches etc). However it comes down to the economics and, in some cases, it costs more to generate the recycled plastic in comparison to the new material. This situation will probably change in the near future.

Christie and Alexa “How many times can a piece of plastic be recycled”
Plastic can be recycled many times. Tests have shown that reprocessing can be carried out ten times without any influence on appearance and performance. This depends on good separation and cleaning of the different plastic types. In reality some fresh plastic will be added at a low level to ensure good performance of the article.

Melon “When is the plastic taken and how can we take it there to be recycled”
Emily from Chorlton “Do you have to recycle to bins”
Jay who is 4 years old “Which recycle bin do you put plastics in”
All of Greater Manchester now collects plastic bottles via your BROWN bin

Arrianne who is 7 years old “How many chairs does it take to make a key ring”
Actually a key ring only uses a small amount of the plastic from a chair. A chair will probably make something like 200 key rings.

Thomas, 8 years old “What happens if you leave your plastic in the rain”
Ben from Stockport “Why do my toys turn white when I leave them in the garden”
Most plastics are water resistant and it is one of the reasons for their wide use.
However some of the pigments that are used to give nice bright colours are not very stable in sunlight and bleach.

Roof Tile – “What about the cost and weathering. Are they fire resistant?”
The roof tiles made from recycled plastic are fire resistant and have passed weathering tests. They are more expensive than conventional tile material but have a much lower carbon footprint.

Georgia “How many machines [for recycling plastics] have been sold and how long do they last for”
David replies “Hmmm a very simple question but not so easy to answer!! We manufacture such a wide range of equipment, and coupled with the fact that the press and shredder are only now really going into production. Here are some figures based around our core product and relevant machinery:
Manufacturing totals something like 36,500 including Heat press, Shredder, Injection Moulder, Vacuum Formers and Line Benders.
Our products are generally regarded as very robust and even in the classroom environment we still repair machines which are about 30 years old, most people change due to modern advancement rather than the machine wearing out, so I guess we could safely put a figure of about 20 years

Manchester Polymer Group would like to thank all of the children and adults who posted such a varied and challenging list of questions.

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