Microwave-assisted nitroxide-mediated polymerization for water-soluble homopolymers and block copolymers synthesis in homogeneous aqueous solution
Résumé
We performed a critical reinvestigation of microwave enhancement of nitroxide-mediated polymerization (NMP) of acrylamide (AM) in aqueous media in the dynamic (DYN) mode with a combination of a conventional hydrosoluble radical initiator and a β-phosphonylated nitroxide (SG1). Based on the results of our previous work, a complementary series of polymerization reactions was carried out between 130 and 160 °C using only the DYN mode to ascertain the existence of a microwave effect. The polymer conversion (p), molar masses, polydispersity index, and viscosity of each sample were measured. The temperature was monitored inside and outside of the vessel using an optical fiber sensor and an IR sensor, respectively. Microwave enhancement of polymerization, temperature control and viscosity of the reaction media were closely related. We also furthered the field of hydrophilic AB diblock copolymer synthesis using a tertiary SG1-based macroalkoxyamine and directly synthesized both poly(acrylamide-b-sodium 2-acrylamido-2-methylpropanesulfonate), a neutral-b-anionic diblock copolymer, and poly(acrylamide-b-3- dimethyl(methacrylamidopropyl)ammonium propanesulfonate), a neutral-b- zwitterionic diblock copolymer, in homogeneous aqueous media.