Intro to Polymers

Polymers Poly – many Mer - parts Long chain molecules made of many smaller repeating units

Classification Natural vs. Synthetic Type of Polymerization –Addition –Condensation Response to Heat –Thermoplastics –Thermosets

Where do polymers come from Natural gas –Linked together by polymerization Start with C 2 H 4

Carbon Chains and Boiling Temperatures Petroleum gas - used for heating, cooking, making plastics –small alkanes (1 to 4 carbon atoms) –commonly known by the names methane, ethane, propane, butane –boiling range = less than 104 degrees Fahrenheit / 40 degrees Celsius –often liquified under pressure to create LPG (liquified petroleum gas) Gasoline - motor fuel –liquid –mix of alkanes and cycloalkanes (5 to 12 carbon atoms) –boiling range = 104 to 401 degrees Fahrenheit / 40 to 205 degrees Celsius Kerosene - fuel for jet engines and tractors; starting material for making other products –liquid –mix of alkanes (10 to 18 carbons) and aromatics –boiling range = 350 to 617 degrees Fahrenheit / 175 to 325 degrees Celsius Gas oil or Diesel distillate - used for diesel fuel and heating oil; starting material for making other products –liquid –alkanes containing 12 or more carbon atoms –boiling range = 482 to 662 degrees Fahrenheit / 250 to 350 degrees Celsius Lubricating oil - used for motor oil, grease, other lubricants –liquid –long chain (20 to 50 carbon atoms) alkanes, cycloalkanes, aromatics –boiling range = 572 to 700 degrees Fahrenheit / 300 to 370 degrees Celsius Heavy gas or Fuel oil - used for industrial fuel; starting material for making other products –liquid –long chain (20 to 70 carbon atoms) alkanes, cycloalkanes, aromatics –boiling range = 700 to 1112 degrees Fahrenheit / 370 to 600 degrees Celsius Residuals - coke, asphalt, tar, waxes; starting material for making other products –solid –multiple-ringed compounds with 70 or more carbon atoms –boiling range = greater than 1112 degrees Fahrenheit / 600 degrees Celsius

Chain Lengths Beaded chain 10,000 carbon atoms – typical polyethylene molecule

Polymerization – Making Chains Addition polymerization Connecting monomers without producing a by-product Usually involves breaking a double bond Requires an initiator Hand-holding simulation chain reaction

Polyethylene LDPE Low density polyethylene ( trees with branches) HDPE High density polyethylene ( trees without branches)

Polymerization – Making Chains Condensation Polymerization Method of forming molecules between 2 different monomers A smaller molecule is also formed as a by-product Also known as a step reaction Example – PETE Nylon demo

Holding chains together covalent bonds – stronger – ex. rubber intermolecular forces – weaker – ex. slime entanglement – ex. HDPE – –(analogy: 50 pieces of yarn – each 6 feet long – jumble and wad them up – throw them down in a pile on the ground – try to pull out one piece – what happens???)

Brief History of Polymers How old are they? Why do we use them? Serendipity books

Polymers Timeline of Plastics 1868 Cellulose Nitrate 1900 Viscose Rayon 1909 Phenol-Formaldehyde 1927 Cellulose Acetate 1933 Polyethylene 1936 Acrylic or Polymethyl Methacrylate 1938 Polystyrene 1939 Nylon 1941 Polyethylene Terephthalate 1942 Low Density Polyethylene 1942 Unsaturated Polyester 1957 Polypropylene 1964 Polyimide 1970 Thermoplastic Polyester 1978 Linear Low Density Polyethylene 1985 Liquid Crystal Polymers

Classification Natural vs. Synthetic Type of Polymerization –Addition –Condensation Response to Heat –Thermoplastics –Thermosets

Elasticity vs. Plasticity Elastic – returns to its original shape after being distorted by a stress –Rubber ball –Elastic in a waistband Plastic – retains new shape after being distorted by a stress –Mud ball –Saran wrap