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The Structure and Properties of Polymers

The Structure and Properties of Polymers. Also known as Bonding + Properties. What is a polymer?. A long molecule made up from lots of small molecules called monomers. Break it down…. Poly- Many Mono- One Meros - Part “ mer ” Macro- Many. Translate this….

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The Structure and Properties of Polymers

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  1. The Structure and Properties of Polymers Also known as Bonding + Properties

  2. What is a polymer? • A long molecule made up from lots of small molecules called monomers.

  3. Break it down… Poly- Many Mono- One Meros- Part “mer” Macro- Many

  4. Translate this… “I’m Hermann Staudinger. I say that rubber has a polymeric structure.”

  5. All the same monomer • Monomers all same type (A) • A + A + A + A  • -A-A-A-A- • eg poly(ethene) polychloroethene PVC

  6. Different monomers • Monomers of two different types A + B • A + B + A + B •  -A-B-A-B- • eg polyamides • polyesters

  7. http://www.umass.edu/molvis/tutorials/dna/dnapairs.htm

  8. So what does a synthetic polymer look like?

  9. Addition polymerisation • Monomers contain C=C bonds • Double bond opens to (link) bond to next monomer molecule • Chain forms when same basic unit is repeated over and over

  10. Copolymerisation • when more than one monomer is used. • An irregular chain structure will result egpropene/ethene/propene/propene/ethene • Why might polymers designers want to design a polymer in this way?

  11. Bellringer: Acid Plant Observations! Hwk: Finish Lab Template! Hwk: Finish Lab Template!

  12. Make Your Own Lab • Task: Design and Conduct (if time!) a lab that will examine “stress-strain behaviors of your “Original Recipe” polymer. • You will have tomorrow to conduct your experiment also • There are 3 types of “stress-strain” behaviors…

  13. Stress-Strain Behaviors • Tensile Strength • Amount of pulling force placed on a material before it breaks • Abrasion Resistance • Toughness of material against scraping, scuffing, or scarring • Puncture Strength • Ability of a material to keep moving objects from perforating a surface.

  14. Test Next Tuesday! Welcome Back! • Bellringer- Acid Plant Lab Observation (only one this week!) • Hwk- QUIA Monday 11/28 (already up!) Congrats to Billy on finishing 41st of 526 at the Turkey Trot 10K!

  15. Today 11/28/11 • Observations • Make sure you get your Recycling # Sheet! • Thanksgiving sweep! • Strengths/Typesof Polymers

  16. What decides the properties of a polymer? • 3 Main Factors: 1.) Chain Length -Longer chain = ____________ 2.) Chain Branching -More branching = ___________ 3.) Interchain Bonding (CROSS LINKS!!!!)

  17. These Factors influence… • Morphology • Form or structure

  18. Crystalline and amorphous polymers • Both amorphous and crystalline areas can be in the same polymer. • Crystalline - regular chain structure - no bulky side groups. • Amorphous- disordered • More crystalline polymer = stronger and less flexible.

  19. Thermoplastics (~85%) • No cross links between chains. • Weak attractive forces between chains broken by warming. (erasers, gelatin) • Change shape - can be remoulded. • Weak forces reform in new shape when cold.

  20. Gelatin…no cross-linking

  21. PVC

  22. Polyethylene terephthalate (like in disposable water bottles)

  23. Sodium Polyacrylate – in diapers!

  24. Polystyrene (styrofoam)

  25. Teflon – nonstick coating on pans…also used to make Gor-Tex

  26. Thermosets • Extensive cross-linking formed by covalent bonds. • Bonds prevent chains moving relative to each other. • Best suited to high-temperature applications – can be brittle when very cold.

  27. Examples of thermosets: • Epoxy resins • Vulcanized rubber (car tires) • Injected molded items like milk crates.

  28. Rubber (below is a monomer)

  29. Examples of amorphous polymers:polyproplene

  30. Nylon

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