PMMA Star-Like Polymers via One-Pot Conventional Free-Radical Copolymerization

Poly(methyl methacrylate)-based star-like polymers (SLPs) were synthesized by a one-pot conventional free-radical copolymerization. Two aryl ester-based cross-linkers, bisphenol A dimethacrylate and 1,4-bis(methacryloxy)benzene, were found to induce SLP formation by reactivity control when copolymerized with methyl methacrylate. The formulation domain diagrams for these systems were established and high monomer concentrations (up to 70 wt-%) were achievable without the occurrence of macrogelation. Kinetic experiments confirmed that the SLP formation occurs via a pseudo two-step mechanism. Parallel plate rheological analysis of the SLP solutions demonstrated that these polymers had low viscosities, typically several orders of magnitude lower than the analogous linear polymer solution.