More Complex Polymersand 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

• Natural rubber

• Neoprene

• Polybutadiene

CH2 CH

CH3

CH2

CH2 CH

Cl

CH2

CH2 CH

H

CH2

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– Sorting– Reclamation– End-use

Problems for plastic

Problems for paper

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, 73