“…Two types of styrene–acrylate copolymer emulsions were prepared, one of which was of a soft matrix (soft‐segmented poly(styrene‐ n ‐butyl acrylate) [S‐PSA]) and the other of a hard matrix (hard‐segmented poly(styrene‐ n ‐butyl acrylate) [H‐PSA]). The following successive steps 11,12 were used to prepare the copolymer emulsions by semicontinuous seeded emulsion polymerization: - Pre‐emulsion process: In a beaker with a high‐speed Ultra‐Turrax homogenizer, 60 mL of distilled water, 6.96 g of Texapon N70, and a mixture of monomers comprising 86.5 g (0.675 mol) of n ‐butyl acrylate and either 64 g (0.614 mol) of styrene for S‐PSA or 85.9 g (0.825 mol) of styrene for H‐PSA, were added one at a time for 30 min at room temperature.
- Seeding process: Emulsion polymerization was done in a four‐necked round‐bottom flask with a nitrogen intake, a condenser, a mechanical stirrer, and a vacuum pump, and that was set up in a heating mantle. In a typical synthesis technique, the flask was filled with 96 mL of distilled water, 3.51 g of Tergitol NP30, 0.39 g of NaHCO 3 buffer, and 0.6 g of KPS.
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