Photo-initiated copolymerization of allyl and vinyl ethers with dialkyl fumarates: A mechanistic investigation by ESI mass spectrometry
Résumé
ESI mass spectrometry was used together with other analytic methods for studying the mechanism of the free-radical donor-acceptor copolymerization of diethyl fumarate with simple vinylether or allylether model monomers. The polymerization of various monomer mixtures was achieved by photo-initiation under soft 365 nm UV light. Diluted solutions as well as solvent-free blends of monomers were reacted in stoichiometric amounts. The obtained copolymers were analyzed, particular attention being paid to their composition in co-monomers and to the nature of the end-groups. ESI mass spectrometry provided detailed information allowing for a semi-quantitative evaluation of the different mechanisms taking place during the initiation, propagation and termination steps of the free radical process. The prime importance of transfer reactions was evidenced for copolymerization involving allyl ethers. Different transfer mechanisms are proposed accordingly.