CHEM 210 SPRING 2014 DR. VILCHIZ POLYMERS

Brief History Ca 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 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 T g

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 PolymerUse PolyethyleneToys, containers, Saran Wrap (new) PolypropyleneFurniture, fiber, carpet PolyvinylchlorideWater pipes, floor tile PolytetrafluoroethyleneTeflon Polyacrylic acidAdhesive & Diaper absorption Polymethacrylic acidThickener 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