1. melt conditions glass transition crystallisation TgTg TmTm POLYMER T g ( o C) Polydimethylsiloxane -123 Poly(vinyl acetate) 28 Polystyrene 100 Poly(methyl methacrylate) 105 Polycarbonate 150 Polysulfone 190 Poly(2,6-dimethyl-1,4-phenylene oxide) 220 Polymers with more flexible backbones, and smaller substituent side groups have lower glass transition temperatures

2. melt conditions glass transition crystallisation TgTg TmTm For semi-crystalline polymers T g T m ( o C) Polyethylene (high density)-120135 Polycaprolactone-6061 Poly(vinylidene fluoride)-45172 Polyoxymethylene-85195 Poly(vinyl alcohol) 85258 Nylon-6,6 49265 Poly(ethylene terephthalate) 69265 Both T g and T m increase with decreasing chain flexibility

3. From Fried, Joel R., “Polymer Science and Technology”, Prentice Hall PTR, Englewood Cliffs, NJ (1995 )

6. Polymer solutions “dilute”, semi-dilute, through to concentrated Rheology: a study of the flow of polymer melts and solutions (shear-thinning, die swell, energy requirements for mold filling, design of mixers, extruders

7. Block copolymer solutions and melts: making patterned surfaces and ordered melt morphologies

8. Scientists, academics < 1930s Industrialists 1830 Charles Goodyear,: vulcanised rubber Hevea brasiliensis +  + S elastomeric material 1847 Christian Schonbern Cellulose + nitric acid cellulose nitrate 1860 Leo Baekeland (Bakelite) phenol-formaldehyde resin 1930s DuPont (USA) nylon, teflon 1938Dow (USA) polystyrene 1939 ICI (UK) LDPE WWII: shortage of natural rubber! “A damned gooey mess” Another failed synthesis

9. Scientists begin to look at complex systems.... 1920’s Hermann Staudinger, German Physical Chemist “long-chained molecules or macromolecules” interacting, separate very long, alkane-like intermediate speciesbut misunderstood. e.g., T m, flow behaviour flexibility

10. Synthesis of polymers biosynthesis step-growth polymerisation All monomer/oligomers/polymers are equally reactive with one another so that there is a distribution of chain sizes chain-growth polymerisation Monomers joined successively to a growing chain A few long chains in a sea of monomers

11. Step-growth polymerisation A n + A m -> A n+m + by-product polydispersity

12. Chain-growth polymerisation A n + A -> A n+1 Monodisperse, high-MW of chains Initiation of the active monomer Propagation of growth of the active (free radical ) chain by sequential addition of monomer Termination of the active chain to give final product

14. Q8: Contrast step-growth and chain-growth mechanisms in the synthesis of linear polymers and include statements comparing the final products of these two classes of synthetic mechanisms.