Controlled/living photopolymerization of methyl methacrylate in miniemulsion mediated by HTEMPO

Abstract

Controlled/living photopolymerization of methyl methacrylate (MMA) in miniemulsion mediated by 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy (HTEMPO) was carried out at ambient temperatures. MMA miniemulsion was prepared by using an anionic surfactant with cetylalcohol as a co-stabilizer. The photopolymerization led to stable lattices and they were obtained with no coagulation during synthesis and no destabilization over time. It was found that the obtained MMA homopolymers exhibited relatively narrow molecular weight distribution (PDI 5 1.27 2 1.36) which was characterized by GPC. The plots of number-average molecular weight in (M n ) vs. conversion and ln([M 0 ]/[M]) vs. time both were linear indicating that the reaction was a controlled/living free radical polymerization.

(Meth)acrylate liquid crystalline polymers for membrane applications

“…The ratio M w / M n found for these polymers varied from 2.3 to 3.5. This is in accordance with the nature of the free radical polymerization process . The presence of the mesogenic comonomer in the feed contributed to a significantly narrower molecular weight distribution in the resulting polymer in comparison to the neat non‐LC homopolymer poly(2‐EHA) ( M w / M n = 3.5).…”

Reversible Deactivation Radical Polymerization Mediated by Nitroxides and Green Chemistry

“…In view of the foregoing, the results of Chinese scientists seem amazing [ 72 ]. They managed to implement the emulsion photopolymerization of MMA using common nitroxide, 4-hydroxy-TEMPO, and photoinitiator Irgacure-184 at room temperature.…”

“…Even though neither nitroxide nor polymer contained chromophore groups, the authors observed a linear growth of M n of the polymer with conversion and Đ = 1.27–1.36. Unfortunately, the mechanism of photoinitiation was not discussed in [ 72 ].…”