Synthesis Of Asymmetrical Divinyl Monomers And Its Ambient Temperature RAFT Copolymerization Under UV-Vis Radiation

The copolymers with pendent Vinyl present various applications such as, beingfurther crosslinked for paint, printing ink and adhesive materials，postfunctionalizingby thiol-ene reaction. It is synthesized by postfunctionalization of polymers,polymerization of vinyl monomers or copolymerization of vinyl monomers and othermonomers. There has been rapid progress in living free radical polymerization,especially in Reversible Addition Fragmentation chain Transfer (RAFT) radicalpolymerization throughout the past decade. RAFT polymerization has become one ofthe most powerful synthetic tools for the preparation of well-defined polymers. Ithas got much attention to prepare vinyl functional polymers by regioselective RAFTpolymerization of asymmetrical divinyl monomers (ADMs) containing two vinylgroups with different reactivities.In this paper, novel ADMs,2-(allyloxy)ethyl acrylate (AOEA) and2-(acryloyloxy) ethyl-5-nobornene-2-carboxylate(AOENbC), are synthesizedcorresponding by esterification of ethylene glycol monoallyl ether and acrylic acid,and Diels-Alder reaction of2-hydroxyethyl acrylate with cyclopentdiene, thenacrylization.The two ADMs are characterized by1H NMR.The ambient temperature RAFT copolymerization of AOEA and AOENbC withacrylates was explored, S-dodecyl-S’-(α,α’-dimethyl-α’’-acetic acid) trithiocarbonate(DDMAT) and (2,4,6-trimethylbenzoyl) diphenylphosphine oxide(TPO) wasseparately used as a chain transfer agent and a photoinitiator in ethyl acetate, a mildvisible radiation with intensity of200μW cm-2at420nm was utilized in this work.It was observed that the controllability of copolymerization decreased and the degreeof branching of copolymer increased with increased ADMs and decreased chaintransfer agent contents in the initial monomer feed, and total monomer conversion.The copolymerization of isobornyl acrylate(iBOA) and AOEA indicated awell-controlled behavior in the case of the total monomer conversion less than70%,the polydispersity indices of copolymers were reasonably low, then themonodispersity and symmetry of the GPC traces suppressed, but the jellification didnot happen even in the case of monomer conversion more than93%. This confirmedthe big disparity in reactivity ratios of AOEA and iBOA. However, thecontrollability of copolymerization of iBOA and AOENbC suppressed clearly as themonomer conversion was more than50%.