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By: Si Man Lam Date: June 7, 2005

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

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