More Complex Polymers
and Recycling
Different States
• Different parts of a plastic may be ordered
or random
Different States
• Different parts of a plastic may be ordered
or random
• Ordered is crystalline
• Random is a glass structure
• Since most polymers have a random
structure
– Cold – glass state
– Warm – rubber state
• Glass transition temperature, Tg,
separates
Tg’s
• Polystyrene - 100°C – plastic utensils
• LDPE - -100°C – soft plastics
– Melts at 108°C
• Natural rubber – way below 0°C – tires
• Polyester - 73°C – non-wrinkle fabrics
Natural Rubber
• Monomer is cis - isoprene
• Slowly flows and is sticky
• 1839 – Charles Goodyear discovered
vulcanization
– X-linking with sulfur
– Elastomer
• Synthetic rubber, hard and brittle – trans
– True synthetic (cis) not until 1955
Monomers
CH3
• Natural rubber CH2
H2C C
H
Cl
• Neoprene H2C C
CH2
H
H
CH2
• Polybutadiene H2C C
H
Conducting polymers
• Alternating single and double bonds in
chain
– Example polyacetylene or polyethyne
• Conduction can be directional
– Along chains but not across
Recycling
• Solid waste: 4 lbs / person per day
– For 250 million people in US – 1 billion
lbs/day
• Make up of garbage?
40 % by volume
20 % by volume
Recycling
• Solid waste: 4 lbs / person per day
– For 250 million people in US – 1 billion
lbs/day
• Make up of garbage?
• In order to recycle, 4 things needed:
– Collection
Problems for plastic
– Sorting
– Reclamation
Problems for paper
– End-use
Amount Recycled
• Aluminum cans – 65%
• Paper – 20%
• Glass – 10%
• Plastic – 3% - Why?
– Economics
– Sorting
• Plastic container codes
H14 – C5
• 16, 19 - 21, 24 - 26, 28 - 30, 57 - 60, 65,
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