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Addition Polymers

polystyrene. Addition Polymers. styrene. polyethylene. ethylene. or. Addition Polymers, continued. Teflon®. acetylene. polyacetylene. “Chain Growth Polymerization”. Addition Polymers, stereochemistry. Ziegler-Natta Catalysts. 1953: The field of polymerization was revolutionized

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Addition Polymers

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  1. polystyrene Addition Polymers styrene polyethylene ethylene or

  2. Addition Polymers, continued Teflon® acetylene polyacetylene “Chain Growth Polymerization”

  3. Addition Polymers, stereochemistry

  4. Ziegler-Natta Catalysts • 1953: The field of polymerization was revolutionized • Ziegler-Natta polymers are linear with almost no branching • Zeigler-Natta polymers are stereochemically controllable: Isotactic, syndiotactic, and atactic forms can all be selectively produced, depending on the catalyst system used. • TiCl4 and AlR3 combine to form an active catalyst for polymerization of many alkenes • Reactive site at titanium is chiral • Nobel prize 1963

  5. Zirconium catalysts • In 1986, Richard Jordan (Iowa) found a zirconium based catalyst. Kaminsky and Brintzinger created a chiral version. JACS1986, 108, 7410 JACS1987, 109, 6544 Polymer is ISOTACTIC

  6. Metallocene catalysts JACS1988, 110, 6255 Polymer is SYNDIOTACTIC

  7. Polymers: Structural Classes • HOMOPOLYMERS: polymers made of identical repeating units • COPOLYMERS: polymers made up of two or more monomers Random copolymer: monomers have a random distribution in the chain Alternating copolymer: Block copolymer:

  8. Condensation Polymers terephthalic acid ethylene glycol Polyethylene terephthalate = PETE

  9. Condensation Polymers, examples polyurethane nylons “Step-Growth Polymerization”

  10. Polymers: classified by physical properties AMORPHOUS vs. CRYSTALLINE (no definable shape) (rigid, highly ordered) Thermoplastics: polymers that can be melted down and reshaped (In other words, they’re recyclable!) Thermosets: Polymers that cannot be heated and cooled reversibly Elastomers: rubbery, stretchy polymers

  11. Spandex A polyurethane with some crystalline portions and some floppier parts, so the resulting polymer is soft and elastic, but it has a “memory”

  12. Styrene-Butadiene Rubber (SBR) A copolymer of 25% styrene, 75% butadiene Natural rubber SBR - major component of chewing gum

  13. Graded Organosilicon Silicone Hardcoat Primer PC Lexan A polycarbonate with unusually high impact strength http://www.youtube.com/watch?v=yHfejwdrMVQ

  14. Dendrimers – monodisperse, globular polymers

  15. Iterative Synthesis of 1,3,5-Polyphenylene Dendrons via C−H Activation, Aaron D. Finke and Jeffrey S. Moore, Org. Lett., ASAP Article

  16. Biodegradable Polymers! Some polyesters have been useful as biodegradable polymers, because their ester linkage is readily hydrolyzable. Polyglycolic acid (PGA) & polylactic acid (PLA), most common A 90/10 copolymer of PGA & PLA is used to make adsorbable sutures (stitches are absorbed by the body in less than 90 days after surgery)

  17. Lifecycle of Plastics

  18. PLA Medical Applications Ring Opening Polymerisation Packaging Fibres

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