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Polymers

Polymers. By: Si Man Lam Date: June 7, 2005. What is a Polymer?. Polymers are commonly known as plastics Long chain of carbon molecules with repeating units joined by covalent bonds Each repeating unit known as a monomer Polymer is Greek for “many parts”

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Polymers

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  1. Polymers By: Si Man Lam Date: June 7, 2005

  2. What is a Polymer? • Polymers are commonly known as plastics • Long chain of carbon molecules with repeating units joined by covalent bonds • Each repeating unit known as a monomer • Polymer is Greek for “many parts” • Imagine a bowl spaghetti – that is how the molecular arrangement of polymers looks

  3. Two Groups of Polymers • Thermoplastic • Soften with heat and harden with cooling • Examples: HDPE, LDPE, PET • Thermosets • Cured or Hardened with heating • Examples: Bakelite, Epoxy, Polyurethane

  4. Natural Polymers • Existed since the beginning of time • Examples include shellac, turtle shells and horns, latex, silk • Chemically modified natural polymers include rubber and gun cotton

  5. World War II: Revenge of the Synth • Reduced supply of natural sources of latex, wool, silk and other materials • Emergence of synthetic polymers • Increased usage and development of nylons, acrylics, neoprene, polyethylene

  6. Bakelite • Developed in 1907 by Leo Baekeland • First synthetic polymer and first widely manufactured plastic • At that time used to make everything from telephones and radios to auto parts, furniture, and jewelry

  7. Polyethylene • Simplest and most basic polymer chain • Made up of a long chain of Ethane molecules (CH3-CH3) • Monomer form is Ethylene (CH2=CH2) • Available in Low Density and High Density Variations • Commonly used for milk bottles, medicine bottles, bags, Toys

  8. PET • Polyethylene Terephthalate • Derivative of polyethylene with terephthalate molecule included in the chain • Durable and clear properties with oxygen and water barrier • Great for soda bottles and drink containers

  9. Teflon • PolyTetraFluoroEthylene • Discovered by Accident by Roy Plunkett at Dupont in 1938 • Secret Weapon of WWII - used to coat bearings and metal surfaces to reduce friction and wear and tear • Now used for non stick pots and pans and dental floss

  10. Other Commonly Used Polymers • Polypropylene (Microwavable Containers) • Polyvinylchloride (Water pipes) • Polystyrene (Foam Cups, Packing Peanuts) • Polycarbonate (aka Lexan, Bulletproof Glass) • Polyamide (Nylon)

  11. What Is Used to Make Plastic Stuff? • Injection Molding • Injection Blow Molding • Injection Stretch Blow Molding • Extrusion Molding • Extrusion Blow Molding • Rotational Molding

  12. Why Use Plastic? • Looks Good • Durable • Flexible • Light Weight • Easy to shape and color • Cheap

  13. The Plastic Age • Stuff made out of plastic is everywhere • Cell phones, computer parts, car parts, tables, chairs, etc. • New uses for plastic being discovered everyday • What used to be glass is now made in plastic • What used to be metal is now made in plastic • What used to be wood is now made in plastic • Plastic has revolutionized the world

  14. References • http://web.umr.edu/~wlf/CHEM381/chap11.html • http://www.calibre.co.nz/plastics.htm • http://www.packagingtoday.com/intronaturalpolymers.htm • http://www.packagingtoday.com/introplasticexplosion.htm • http://www.teachingplastics.org/hands_on_plastics/intro_to_plastics/teachers.html

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