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Reading (Odian Book): Chapter 1-4, 1-5, 1-6

Reading (Odian Book): Chapter 1-4, 1-5, 1-6. Polymer Parameters. Chemical structure Chemical composition and distribution Sequence length and distribution Molecular weight and distribution Chain isomerism Morphology Topology Additives Cost. Chain Isomerism. Regio-isomers

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Reading (Odian Book): Chapter 1-4, 1-5, 1-6

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  1. Reading (Odian Book): Chapter 1-4, 1-5, 1-6

  2. Polymer Parameters • Chemical structure • Chemical composition and distribution • Sequence length and distribution • Molecular weight and distribution • Chain isomerism • Morphology • Topology • Additives • Cost

  3. Chain Isomerism • Regio-isomers • Geometric isomers • Stereo-isomers • Conformational isomers

  4. Conformational Isomers

  5. Conformational Isomers 4.5 3.8 1.0 - 180 - 120 - 60 0 +60 +120 +180 Energy (kcal/mol)

  6. Amorphous Morphology Glass Transition Temperature

  7. Copolymer Synthesis Tetrafluoroethylene(TFE) 2,2-bis(trifluoromethyl)-4,5-difluoro-1,3-dioxole(PDD) 350 300 250 in °C 200 g T 150 100 50 50 60 70 80 90 100 PDD in wt-% Udo, M.; Resnick, P.; Kipp, B. ; DeSimone*, J.M. Macromolecules2003, 36, 7107

  8. Mechanical Properties • Tensile strength • Resistance to stretching • Compressive strength • The extent to which a sample can be compressed before it fails • Flexural strength • Resistance to breaking or snapping when bent • Impact strength • Measure of toughness, ability to withstand sudden impact • Fatigue • Ability to withstand repeated tensile, flexural or compressive stress

  9. Mechanical Properties • Tensile stress (σ) • σ = F / A • dynes per square cm • Tensile strain (ε) • ε = ΔL / L • Tensile Modulus (E) • E = σ / ε

  10. Processing of Amorphous Polymers Tprocessing = ?

  11. Symmetry Requirements forCrystallinity Atactic Polystyrene Tm = N/A Tg = 105 °C Syndiotactic Polystyrene Tm = 270 °C Tg = 105 °C

  12. Processing of Semicrystalline Polymers • Cool a polymer melt… • Translational, rotational and vibrational motions decrease… • If certain symmetry elements are met, crystallization can take place just below Tm • Continue to cool, long-range backbone segmental motion ceases at Tg • Side groups and backbone para-phenylene still in motion below Tg

  13. Trashcan Isotactic Polypropylene Tg = - 20 °C Tm = 170 °C

  14. Processing of Semicrystalline Polymers Tprocessing = ?

  15. Processing of Semicrystalline Polymers

  16. Differential Scanning Calorimetry

  17. DSC of a Crystalline Polymer Endo

  18. DSC of a Crystalline Polymer

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