Synthesis of Well-Defined ω-Oxabornenyl Poly(ethylene oxide) Macromonomers via Click Chemistry and their Ring-Opening Metathesis Polymerization
Résumé
ω-Oxanorbornenyl poly(ethylene oxide) monomethyl ether macromonomers were synthesized with molecular weights ranging from 500 g/mol to 5000 g/mol through the Huisgen 1,3-dipolar cycloaddition between acetylene-functionalized oxanorbornene and ω−azido poly(ethylene oxide) monomethyl ether. Thermal analysis showed that the ω-exo-norbornenyl end-group of the macromonomers is converted into a maleimide group through a retro-Diels−Alder process at 130 °C. Ring-opening metathesis polymerization (ROMP) of these macromonomers was investigated using Grubbs’ catalyst in dichloromethane at room temperature. Poly(oxanorbornene)-g-poly(ethylene oxide)s were obtained with polydispersities between 1.04 and 1.17 and molecular weights between 9900 and 57 800 g/mol leading to comb or brush copolymers according to the lengths of backbone and graft chains.