C+-+categories+of+plastics

= “What are the categories of plastics and why are only some recyclable?”﻿ =


 * “Plastic is the common term for a broad range of synthetic or semi-synthetic organic materials used for manufacture of a variety of domestic and industrial products.” 1


 * There are 7 main types of recyclable plastics:
 * 1) PET/PETE (polyethylene terephthalate) – most commonly recycled; i.e. plastic jars, drink bottles, plastic wrap, oven-ready meal trays, etc.
 * 2) HDPE (high-density polyethylene) – i.e. shampoo bottles, milk bottles, detergent containers, etc.
 * 3) PVC (polyvinyl chloride) – generally opaque, less frequently recycled; i.e. clear food packages, food trays, etc.
 * 4) LDPE (low-density polyethylene) – i.e. frozen food bags, garbage can liners, carrier bags, light & flexible film, etc.
 * 5) PP (polypropylene) – mostly used in automobile and building industries; i.e. car battery casings, margarine tubs, plastic drinking straws, etc.
 * 6) PS (polystyrene) – i.e. some packing foam, plastic cutlery, protective packaging for electronic goods, yogurt tubs, etc.
 * 7) OTHER – composed of a different material than those listed above OR composed of a combination of two or more materials listed above; mostly used to make 3-5 gallon reusable containers


 * Though many types of plastics can be recycled, not all of them are recyclable
 * One difficulty faced is that making an automated system that sorts out different types of plastics is very difficult (so it requires a lot of manual labour)
 * Every type plastic has a critical temperature point, in which it will either:
 * Melt down into a flexible structure that can be shaped and remade into something else, or
 * Burn & become destroyed, making them unable to be reformed
 * <span style="font-family: 'Comic Sans MS',cursive;">Therefore, the intermolecular bonds of the compound determines the way that the plastic degrades
 * <span style="font-family: 'Comic Sans MS',cursive;">Thermoset plastics with stronger, lattice (diagonal lined) structures do not melt like thermoplastics, they just burn, making it impossible for it to be reformed

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<span style="font-family: 'Comic Sans MS',cursive;">Bibliography:

 * 1) <span style="font-family: 'Comic Sans MS',cursive;">The Gemini Geek (2010). Why Some Plastics Are Non Recyclable. The Gemini Geek – Geeks Redefined. Retrieved October 8, 2010 from <[]>.
 * 2) <span style="font-family: 'Comic Sans MS',cursive;">Mikael Gröning, Ann-Christine Albertsson (2005). Polymer recycling and degradation. AccessScience. ©McGraw-Hill Companies. Retrieved October 10, 2010 from <[]>.
 * 3) <span style="font-family: 'Comic Sans MS',cursive;">Waste Online (2010). Plastics recycling information sheet. Waste Online. Retrieved October 8, 2010 from <[]>.
 * 4) <span style="font-family: 'Comic Sans MS',cursive;">City of Toronto (2010). Blue Bin Recycling Program. City of Toronto: Solid Waste Management. Retrieved October 10, 2010 from <[|http://w][|ww.toronto.ca/garbage/bluebox/index.htm]>.


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