1. HIDROCARBON GROUPS

2. Polymer = many mers POLYMER MICROSTRUCTURE

3. POLYMER MATERIALS

5. Covalent chain configurations and strength: Direction of increasing strength MOLECULAR STRUCTURE Homopolymers

6. MOLECULAR STRUCTURE Copolymers

7. MOLECULAR STRUCTURE Copolymers

8. Molecular weight, M w : Mass of a mole of chains. Tensile strength (TS): --often increases with M w. --Why? Longer chains are entangled (anchored) better. % Crystallinity: % of material that is crystalline. --TS and E often increase with % crystallinity. --Annealing causes crystalline regions to grow. % crystallinity increases. MOLECULAR WEIGHT & CRYSTALLINITY

9. CRYSTALLINITY

10. POLYMER CRYSTALS

11. 6 Compare to responses of other polymers: --brittle response (aligned, cross linked & networked case) --plastic response (semi-crystalline case) TENSILE RESPONSE: ELASTOMER CASE

12. Decreasing T... --increases E --increases TS --decreases %EL T AND STRAIN RATE: THERMOPLASTICS

13. Stress relaxation test: --strain to   and hold. --observe decrease in stress with time. Relaxation modulus: Data: Large drop in E r for T > T g. (amorphous polystyrene) TIME DEPENDENT DEFORMATION

14. VULCANIZATION

15. TENSILE RESPONSE: BRITTLE & PLASTIC

16. CRYSTALLIZATION, MELTING AND GLASS TRANSITION PHENOMENA IN POLYMERS Dependence of polymer properties as well as melting and glass transition temperatures on molecular weight

17. POLYMER TYPES

18. FORMING TECHNIQUES FOR PLASTICS