Category:Working Plastics - Revision history

DT Online at 19:50, 16 November 2016

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			[[File:Thermoforming animation.gif\|400px\|right\|Thermoforming animation]]
	Since the development of early [https://en.wikipedia.org/wiki/Plastic '''Plastics'''], such as [https://en.wikipedia.org/wiki/Celluloid '''Celluloid'''], [https://en.wikipedia.org/wiki/Bakelite '''Bakelite'''], [https://en.wikipedia.org/wiki/Poly(methyl_methacrylate) '''Perspex'''] and [https://en.wikipedia.org/wiki/Nylon '''Nylon'''], an ever-expanding variety now surrounds us, not only mimicking traditional or natural materials but also bringing with them particular properties and characteristics. The word ‘plastic’ is derived from ‘plastikos’, a Greek word meaning ‘capable of being shaped or molded’.		Since the development of early [https://en.wikipedia.org/wiki/Plastic '''Plastics'''], such as [https://en.wikipedia.org/wiki/Celluloid '''Celluloid'''], [https://en.wikipedia.org/wiki/Bakelite '''Bakelite'''], [https://en.wikipedia.org/wiki/Poly(methyl_methacrylate) '''Perspex'''] and [https://en.wikipedia.org/wiki/Nylon '''Nylon'''], an ever-expanding variety now surrounds us, not only mimicking traditional or natural materials but also bringing with them particular properties and characteristics. The word ‘plastic’ is derived from ‘plastikos’, a Greek word meaning ‘capable of being shaped or molded’.

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	The almost universal use of plastics for packaging and other throw-away items is causing considerable environmental issues since they do not rot very easily. Also, most plastics are made from oil which is a diminishing resource so there is increasing demand for them to be recyclable. Much work currently therefore, is focussed on the research and development of [https://en.wikipedia.org/wiki/Biodegradable_plastic '''Biodegradable Plastics'''] which are derived from renewable resources.		The almost universal use of plastics for packaging and other throw-away items is causing considerable environmental issues since they do not rot very easily. Also, most plastics are made from oil which is a diminishing resource so there is increasing demand for them to be recyclable. Much work currently therefore, is focussed on the research and development of [https://en.wikipedia.org/wiki/Biodegradable_plastic '''Biodegradable Plastics'''] which are derived from renewable resources.


			[[Category:Skills and Processes]]

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 <span style="color: green">'''Note:''' this phrase also defines '''[[Malleability]]''' and many materials have a '''[[Young's Modulus|Plastic Stage]]''' as they are deformed. To avoid confusion, '''DT Online''' uses the term '''Plastics''' as both a singular and plural noun)</span>)''
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 The almost universal use of plastics for packaging and other throw-away items is causing considerable environmental issues since they do not rot very easily. Also, most plastics are made from oil which is a diminishing resource so there is increasing demand for them to be recyclable. Much work currently therefore, is focussed on the research and development of [https://en.wikipedia.org/wiki/Biodegradable_plastic '''Biodegradable Plastics'''] which are derived from renewable resources.

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Since the development of early [https://en.wikipedia.org/wiki/Plastic '''Plastics'''], such as [https://en.wikipedia.org/wiki/Celluloid '''Celluloid'''], [https://en.wikipedia.org/wiki/Bakelite '''Bakelite'''], [https://en.wikipedia.org/wiki/Poly(methyl_methacrylate) '''Perspex'''] and [https://en.wikipedia.org/wiki/Nylon '''Nylon'''], an ever-expanding variety now surrounds us, not only mimicking traditional or natural materials but also bringing with them particular properties and characteristics. The word ‘plastic’ is derived from ‘plastikos’, a Greek word meaning ‘capable of being shaped or molded’.

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<span style="color: green">'''Note:''' this phrase also defines '''[[Malleability]]''' and many materials have a '''[[Young's Modulus|Plastic Stage]]''' as they are deformed. To avoid confusion, '''DT Online''' uses the term '''Plastics''' as both a singular and plural noun)</span>)''
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Synthetic* [https://en.wikipedia.org/wiki/Plastic '''Plastics'''] are chemically produced from oil and a wide, possibly infinite, variety is possible, but they all fit into one of two groupings:

* [https://en.wikipedia.org/wiki/Thermoplastic '''Thermoplastics'''] - these can repeatedly be softened by heating and will return to a rigid state when cooled.
** this group includes: [https://en.wikipedia.org/wiki/Poly(methyl_methacrylate) '''Acrylic'''], [https://en.wikipedia.org/wiki/Polycarbonate '''Polycarbonate ''(PC)'''''], [https://en.wikipedia.org/wiki/Polyethylene '''Polyethylene'''], and [https://en.wikipedia.org/wiki/Polypropylene '''Polypropylene'''].
* [https://en.wikipedia.org/wiki/Thermosetting_polymer '''Thermosets'''] - these are initially ‘cured’ ''(or set)'', often by mixing with a ‘hardener’ which creates a heat producing ''([https://en.wikipedia.org/wiki/Exothermic_process '''Exothermic'''])'' chemical reaction and, once set cannot be softened again by further heating.
** this group includes: [https://en.wikipedia.org/wiki/Polyester '''Polyester Resin'''], [https://en.wikipedia.org/wiki/Epoxy '''Epoxy Resin'''], [https://en.wikipedia.org/wiki/Bakelite '''Bakelite'''] and [https://en.wikipedia.org/wiki/Melamine '''Melamine'''].
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<span style="color: green">'''*Note:'''
Several natural materials may also be classified as '''''Plastics'''''. These include: [https://en.wikipedia.org/wiki/Cellulose '''Cellulose'''], [https://en.wikipedia.org/wiki/Keratin '''Horn'''], [https://en.wikipedia.org/wiki/Amber '''Amber'''], and [https://en.wikipedia.org/wiki/Shellac '''Shellac'''].
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[[File:Polyethylene-terephthalate-3D-balls.png|400px|right|Polyethylene-terephthalate-3D-balls]]
[https://en.wikipedia.org/wiki/Plastic '''Plastics'''] are formed by long chains of carbon based molecules, or [https://en.wikipedia.org/wiki/Polymer '''Polymers'''], strongly bonded to each other. The [https://en.wikipedia.org/wiki/Polymer#Chain_length '''Polymer Chains'''] are either joined to each other with weak [https://en.wikipedia.org/wiki/Van_der_Waals_force '''van der Vaals Forces'''] to create [https://en.wikipedia.org/wiki/Thermoplastic '''Thermoplastics'''] or much stronger [https://en.wikipedia.org/wiki/Cross-link '''Cross-Linking'''] which results in [https://en.wikipedia.org/wiki/Thermosetting_polymer '''Thermosets'''].

The almost universal use of plastics for packaging and other throw-away items is causing considerable environmental issues since they do not rot very easily. Also, most plastics are made from oil which is a diminishing resource so there is increasing demand for them to be recyclable. Much work currently therefore, is focussed on the research and development of [https://en.wikipedia.org/wiki/Biodegradable_plastic '''Biodegradable Plastics'''] which are derived from renewable resources.