Polymer Chemistry

40 lessons, pages 3521–3560.

  1. What Is a Polymer? — Monomers, repeat units, degree of polymerisation and macromolecular scale
  2. Classifying Polymers — Natural vs synthetic, thermoplastics, thermosets and elastomers
  3. Polymer Architecture — Linear, branched, network, star and dendritic chains
  4. Copolymers and Sequence — Random, alternating, block and graft copolymers
  5. Polymer Nomenclature and Repeat Units — Source-based and structure-based naming; drawing constitutional repeat units
  6. Two Mechanisms of Polymerisation — Step-growth vs chain-growth: how chains build up over time
  7. Step-Growth Polymerisation: Principles — Functional-group reactivity, equal reactivity assumption and oligomer build-up
  8. Condensation Polymers: Polyesters — Diol plus diacid linkages, PET and the loss of small molecules
  9. Condensation Polymers: Polyamides — Nylon-6,6, nylon-6 and hydrogen bonding between amide links
  10. The Carothers Equation — Extent of reaction p and number-average degree of polymerisation 1/(1 − p)
  11. Stoichiometric Imbalance and Chain Stoppers — Modified Carothers equation with ratio r and monofunctional reagents
  12. Step-Growth Kinetics — Second-order and self-catalysed polyesterification rate laws
  13. Network Formation and Gelation — Multifunctional monomers, gel point and thermoset curing
  14. Chain-Growth Polymerisation: Principles — Active centres, initiation, propagation and termination
  15. Free-Radical Initiation — Initiator decomposition, radical efficiency and rate of initiation
  16. Propagation and Termination — Combination, disproportionation and the steady-state assumption
  17. Kinetic Chain Length and Chain Transfer — Rate of polymerisation, kinetic chain length and chain-transfer agents
  18. Ionic Chain Polymerisation — Cationic and anionic mechanisms and monomer suitability
  19. Living Polymerisation — Absence of termination, narrow distributions and block copolymer synthesis
  20. Coordination Polymerisation and Tacticity — Ziegler–Natta and metallocene catalysts; isotactic, syndiotactic and atactic chains
  21. Ring-Opening Polymerisation — Ring strain as driving force; lactones, lactams and cyclic ethers
  22. Step vs Chain Growth Compared — Monomer consumption, molar mass versus conversion and typical products
  23. Why Polymers Have a Molar-Mass Distribution — Statistical chain growth and the need for averages
  24. Number-Average Molar Mass — Defining and calculating Mn from chain counts
  25. Weight-Average Molar Mass — Defining and calculating Mw and why it weights large chains
  26. Dispersity — Mw/Mn, the most probable distribution and values for different mechanisms
  27. Other Molar-Mass Averages — Z-average and viscosity-average molar masses
  28. Measuring Molar Mass: Colligative and End-Group Methods — Osmometry and end-group analysis give Mn
  29. Measuring Molar Mass: Light Scattering and Viscometry — Static light scattering for Mw; intrinsic viscosity and the Mark–Houwink equation
  30. Size-Exclusion Chromatography — Separation by hydrodynamic volume, calibration and reading distributions
  31. Polymer Chains in Space — Random coils, end-to-end distance and chain flexibility
  32. Amorphous and Crystalline Polymers — Chain folding, spherulites and degree of crystallinity
  33. The Glass Transition — Tg as onset of segmental motion; glassy vs rubbery states
  34. Tg and Melting Compared — Second-order-like transition vs first-order melting; Tg and Tm in semicrystalline polymers
  35. Factors That Control Tg — Backbone stiffness, side groups, polarity, molar mass and cross-linking
  36. Plasticisers, Copolymers and the Fox Equation — Lowering and tuning Tg in blends and copolymers
  37. Measuring Tg — Differential scanning calorimetry, dilatometry and dynamic mechanical analysis
  38. Polymer Mechanical Properties — Stress–strain behaviour, viscoelasticity and rubber elasticity
  39. Polymers, Sustainability and Recycling — Degradation, biodegradable polymers and mechanical versus chemical recycling
  40. Polymer Chemistry: Unit Review — Mechanisms, molar-mass averages and Tg brought together