Polymers

Polymers

1. What are the 2 types of polyethene

   • How are they made
     • ethene is made by Cracking crude oil into gasoline or they can be made my modifying a natural gas (a methane ethane and propane mix) HDPE is made by combining ethene monomers
   • There is LDPE (low density polyethene) and HDPE (high density polyethene). LDPE has may branches on its polymer molecules and therefor its relative strength is weak and its max usable temperature is 85°C, whereas HDPE has few branches on its polymer molecules and therefore is stronger and can be used at a much higher temperature (120°C)

2. Thermosetting and thermosoftening

   • The polymer chains in thermosetting are interlinked - separate polymers are joined together to make one big polymer
     • Thermosetting plastics are Good electrical insulators, they are hard, they are brttle and they resist chemicals well, this means they are good for PCB's and surface coating
   • The polymer chains in thermosoftening plastics are not interlinked - each polymer is separate from all the others
     • A thermosoftening polymer is a polymer that can be made soft by heat easily, this makes it good for things that need be changed a lot and then set when they are made cool again

3. plastics used in everyday life, and why?

   • Polyvinyl Chloride
     • Anything needed to be cheap and malleable
   • polypropene
     • packaging, labelling, textiles, stationary, reusable containers
       • Light, hard, stiff, transparent
   • Polystyrene
     • Smoke detector housings, dinnerware, plastic cutlery, cd cases
   • Polyethylene Terephthalate
     • Film, packaging, containers (from bottles to buckets)
     • This is the most widely used and Most manufactured plastic

4. What are the problems associated with plastic waste disposal?

   • landfill
     • When waste polymers are disposed of in landfill sites, the use up valuable space, and suitable sites are often filled up too quickly
   • Incineration
     • When waste polymers are incinerated (burned) they. produce a lot of energy, this energy can be used to heat homes or to generate electrify. But when incinerating polymers, carbon dioxide (a greenhouse gas) is produced, which is bad for the environment

5. Research how new plastics are being made to include light sensitive plasters, PET, hydrogels, and shape memory polymers.

   • Hydrogels are polymer chains that have a few cross linking chains between them. it is a matrix that can trap water. For example they are used in plasters that are specially for burns, so the body an heal in moist, sterile conditions.
   • shape memory polymers will change back to a certain state when some sort of stimulus occurs, such as heating up.

6. What are biodegradable polymers? How are they made? Can you explain their disadvantages?

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