Transcript POLYMERS - Virginia State University

POLYMERS
CHEM 210
SPRING 2014
DR. VILCHIZ
Brief History
 Ca. 1600 BC Earliest known polymer work
 Pre-Columbian Mexico’s rubber industry

Latex from the rubber tree + juice from morning glory plant 
rubber for different products
 1839 Vulcanization (Charles Goodyear)
 Rubber + S  durable material w/ crosslinks (Car Tires)
 1861 Colloidal Science is born (Thomas Graham)
 1907 Oldest synthetic plastic (Leo Bakeland)
 1917 development of x-ray crystallography
 1925 x-ray crystallography of cellulose proves
polymers are long structures
Brief History Con’t
 1927 Large production of Vinyl Chloride begins
 1930 Polystyrene is invented
 1938 Nylon is produced for the first time
 Wallace Carothers @ the Dupont Company
 1940’s Natural Rubber shortage due to WWII
 Opens market for synthetic rubber
 1940’s Work done on the kinetics of polymerization
 1941 Polyethylene is developed
 1950’s Polymers with stereochemistry developed
 Ziegler-Natta
Brief History Con’t
 1970’s Engineering/Conductive Polymers developed
 1970 Ekonol (moldable polymer) is developed
 James Economy
 1971 Liquid Crystal Polymers Developed
 1971 Kevlar is developed
 Patented by S. Kwolek among 37 polymer science patents
 1976 Polymers becomes the US most widely used
material
 1980-Present making polymers “green”
 2010’s- Polymer wires
What are Polymers?
 Polymers are compounds containing 1 or more
repeating unit.
 Unlike regular compounds polymers do not have a
clearly defined molecular weight
 They can be crystalline or amorphous
 They are classified depending on their starting
materials (monomer)
Families of Polymers
 1. Nylons
 2. Polyurethanes
 3. Polyvinyls
 4. Polyesters
 5. Polyethers/Polyalcohols
 6. Polycarbonates
 7. Phenolics
 8. Polyimides
Properties
 Tacticity
 Syndiotactic, Isotactic, Atactic
 Cross-linking
 Affects rigidity
 Branching
 Affects crystallinity
 Gyration
 Tg
Types of Polymers
 Thermoplastic
 Heat/cool many times
 Elastomer
 Polymer containing “few” cross-links so it can stretch
 Thermoset
 Polymer that can withstand heat (shapewise)
 Blends
 Mixtures of polymers created to protect the properties of a
product
Polymerization
 There are two main polymerization “reactions”
 Free-Radical Polymerization
 Condensation Polymerization
 Free-radical Polymerization
 Requires an Initiator and a quencher
 Produces “living” polymers
 Produces “high-density” polymers
 High MW polymers
 Low polydispersity samples
Polymerization
 Condensation Reactions
 Produces Low-Density Polymers
 Large polydispersity samples
 No initiator or quencher required
 Water byproduct
Polymer Uses
Polymer
Use
Polyethylene
Toys, containers, Saran Wrap (new)
Polypropylene
Furniture, fiber, carpet
Polyvinylchloride
Water pipes, floor tile
Polytetrafluoroethylene
Teflon
Polyacrylic acid
Adhesive & Diaper absorption
Polymethacrylic acid
Thickener
Poly(methylmethacrylate)
Pexiglass/Safety Glass
Recycling
 Expensive
 Each polymer has its own recycling process
 There has to be “high demand” for the individual polymer
 It has to be “easy” to transport
#
 What do the Numbers mean?
 They tell you what the polymer used in the container is.
Recycling by Numbers
 #1 PETE (PolyEthylene Teraphthalate)
 Soda Bottles and Food Trays (high demand)

End up as carpets
 #2 HDPE (High Density PolyEthylene)
 Milk & Water Jugs (high demand)
If “colorless” ends up as a new container
 If colored ends up as “lumber”

 #3 “vinyl” or PVC (PolyVinylChloride)
 White pipes (low demand)
Recycling by Numbers Con’t
 #4 LDPE (Low Density PolyEthylene)

Plastic bags (high demand but “hard” to transport)

They end up as new bags or “lumber”
 #5 PP (PolyPropylene)

Tough food containers (yogurt, butter)

Not enough “demand” to make it profitable
 #6 PS (PolyStyrene)

Not cost effective to recycle but still recycled
Inflated PS ends up as packaging
 Compacted PS ends up as CD/DVD cases and utensils/containers

 #7 Other (mixture)

Can’t be recycled as the mixture can’t be separated