2.3. Seeded Emulsion Polymerization with Ethylene Glycol Dimethacrylate (EGDMA)

Typically, the 170 nm poly(n-BMA) latex, was used to seed a final growth reaction in a 3:1 mass ratio (poly(n-BMA-co-EGDMA) second stage at 1 w% EGDMA to poly(n-BMA) seed) targeting a final 265 nm particle diameter by seeded emulsion polymerization at 70 °C with variations in monomer feed rate. Feed times employed were 0 h (batchwise reaction), 0.5 h, 1 h, 1.5 h and 2 h, respectively, all for the same mass of monomer. After feeding, the reaction was held at 70 °C until a total reaction time of 3 h was achieved. Typically, experiments utilized a KPS concentration of 0.01 M with SDS as stabilizer.

Samples were taken periodically from the reactor for monitoring the dynamics of kinetics and gel formation development during the seeded emulsion co-polymerization with divinyl monomer present. The sampling intervals were varied based on feeding time and samples were quenched with hydroquinone.