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Plastics

1. How plastics are made

   • Making plastics
     • sun - plant photosynthesis - sugar fermented
       • with micro organisms - PHB - moulded
       • ( - bio degreaded- CO2 emitted - absorbed by plant photosynthesis)
   • Polymer formula
   • Polymer chemical processes

2. Properties and uses of polymers

   • Types of plastics
     • Thermosoftening
       • can be melted
       • can be remoulded
       • flexible
       • not heat tolerant
       • not many cross sections
     • Thermoset
       • degrade in heat
       • rigid
       • cant be remoulded
       • lots of cross sections
   • Novel plastics
     • Low density polyethene (LPDE)
       • low density (0.92)
       • flexible (12)
       • side branches
       • low melting point (8.5)
       • lots of branches spread out
     • High density polyethene (HDPE)
       • high density (0.95)
       • stiff (31)
       • few side branches
       • high melting poins (120)
       • few branches close together
   • Polymers

3. Problems and disposal of plastic

   • Methods of plastic disposal
     • landfill
       • pollution
       • land use
     • incineration
       • uses lot of energy
       • pollution and global warmiing
     • biodegrading
       • not very common
     • recycling
       • time consuming
   • Recycling
     • advantages
       • reduced pollution and global warming
       • reduced energy consumption
       • reduced landfill sites
     • disadvantages
       • less durable quality
       • not widespread
       • high intitial
       • unsafe/unhygienic sites
   • Replacing plastics
     • not as cheap
     • not as versitile
     • not as durable
   • Biodegradable plastic
     • food packaging
     • agriculture
     • medical