Copolymerization of Styrene with 2-Ethylhexyl Acrylate and 2-Ethylhexyl Methacrylate by Semibatch Emulsion Polymerization Using BlocBuilderMA as Macroinitiator

Using BlocBuilderMA (BB) as a macroinitiator, stable and controlled latexes of polystyrene (PS), poly 2-ethylhexyl acrylate (PEHA), poly 2-ethylhexyl methacrylate (PEHMA), and copolymers PS-b-PEHA and PS-b-PEHMA with solids contents up to 40 wt % were obtained. Using different concentrations of styrene (St) in the nucleation step, it was possible to obtain colloidal dispersions with particle size ranging from ≈72 nm to ≈500 nm, conversions up to ≈100%, nitroxide efficiencies (NEff) up to ≈0.93, and number-average molecular weights (Mn) from ≈8000 to ≈81 000 g/mol. These polymerizations were conducted using a very simple and fast process because it was not necessary to ionize BB, to use alkaline conditions, or to have a long seed formation step since the seed is formed in situ during the heating ramp. These features make this process a good candidate for scale-up and eventual industrial production.