2. Chains and Rings Litterature Talk July, Monday 14th Alex

3. Chains and Rings Litterature Talk July, Monday 14th Alex

4. Chains and rings Equilibria Thermodynamics Applications (Cyclics Corp.) Making Rings

5. Rings and Chains Equilibria Lactide

6. Rings and Chains Equilibria Oxymethylene Sulfur Source: Allcock HR, Journal of macromolecular science – review in macromolecular chemistry, Vol C4, Issue 2, p149-189 (1970)

7. Thermodynamics Source:Allcock HR, Journal of macromolecular science – review in macromolecular chemistry, Vol C4, Issue 2, p149-189 (1970) R x +C y C x+y  G =  H - T  S  H<0  S<0 Ceiling temperature  S>0 Chains only  H=0  S<0 Chains only  S>0 Rings only  H>0  S<0 Rings only  S>0 Flooring temperature

8. Thermodynamics Ring size influence equilibrium: 3,4: Negative significant enthalpy, high polymer conversion 5 to 7: Enthalpy term roughly equivalent to entropy term 8 to 10: same conclusion than 3 and 4 membered rings Greater: Easy polymerization T c depends on: Monomer concentration (T c increases with monomer concentration for exothermic reaction) Pressure (T c increases with pressure) Sources: Ivin K.J., Journal of Polymer Science: Part A: Polymer Chemistry, Vol 38(12), 2137-2146 (2000) Hocker H, Keul H, Advanced Materials, V6, I1, p21-36 (1994)

9. Why using rings? Rapid ring-opening polymerization No measurable exotherm No by-products (because no end-groups) Yields high molecular weight polymers Low viscosity Low melting point when used in a mixture of rings Source: Brunelle D.J., Journal of Polymer Sciences: Part A: Polymer Chemistry, Vol 46, 1151-1164 (2008)

10. Cyclics Corp. Use of cyclic butylene terephthalate –Low Viscosity –Thermal stability –Compatible with other polymers Produces polybutylene terephthalate –Good stiffness –Good chemical resistance –Good dimensional stability –Light weight Source: www.cyclics.com

11. Cyclics Corp. Applications: Rotational molding Casting Composites Coatings Additives Source: www.cyclics.com

12. Making rings Early work allowed production of rings only through long reaction times, low productivity and extensive purification Work by Daniel Brunelle, from GE Global Research, lead to the many patents concerning ring polymerization, which in turn lead to Cyclics Corp. Source: Brunelle D.J., Journal of Polymer Sciences: Part A: Polymer Chemistry, Vol 46, 1151-1164 (2008)

13. Making rings: characterization Work on Bisphenol A polycarbonate Reverse phase HPLC with dual wavelength detector set at 254 and 285nm Linear oligomers absorb strongly at 285 and 254 nm Cyclic compounds absorb 50 times more at 254 than at 285 nm. Source: Brunelle D.J., Journal of Polymer Sciences: Part A: Polymer Chemistry, Vol 46, 1151-1164 (2008)

14. Making rings Mechanism: Hydrolysis and condensation Source: Brunelle D.J., Journal of Polymer Sciences: Part A: Polymer Chemistry, Vol 46, 1151-1164 (2008) All reactions must happen fast, to prevent build-up in reactant concentration and formation of polymer (higher than usual amount of catalyst) Good pH control is paramount to have reactive phenoxides in solution, and not phenols, without promoting cycle hydrolysis Catalyst used is very important and can lead to all possible outcomes: Example of catalyst usedOutcome Et 3 NCyclics and polymer pyridineLinear oligomers Pyridine (more severe conditions) Hydrolysis Polyethylene glycolNo reaction bischloroformate

15. Conclusion Research has been done on rings/chains equilibrium since the 50’s Using rings polymerization gives better handling conditions and higher MW polymers, with no by-products Good reaction control (pH, catalyst…) allows formation of rings instead of chains