Effect of 2-hydroxyethyl methacrylate content on the emulsion polymerization process of styrene–butyl acrylate–acrylic acid: Chemical, thermal and film properties of polymer latex

In this study, a series of hydroxyl functionalized styrene acrylate latex particles were prepared using the 2-hydroxyethyl methacrylate (HEMA) monomer as a hydroxyl source via the seeded emulsion polymerization method. The effect of anionic/nonionic surfactant on the morphology and thermal behaviors of the prepared polymer latex particle was studied. The structure and morphology of polymer latex particles were characterized using FT-IR, 1 H-NMR, DSC, TGA, DLS, and SEM techniques. The water-soluble HEMA monomer led to homogeneous nucleation, in addition to micellar nucleation observed due to the water-insoluble styrene and butyl acrylate monomers. The unmodified polymer latex particle had a glass transition temperature ( T g ) of 7.5 °C. The T g of hydroxyl functionalized polymer latex particle had 13.9, 14.8, 19.0, and 18.8 °C in the presence of 2.5, 4.0, 6.0, and 10.0 mass % HEMA, respectively. The average particle size was 95.30, 98.30, 115.90, 167.00, and 153.50 nm at the polymer latex content of 0, 2.5, 4.0, 6.0, and 10.0 mass % HEMA, respectively. With the addition of 1.35 mass % NP-40, the particle size of polymer latex increased from 167.00 to 218.50 nm in the presence of 0.9 mass % SLS. The addition of nonionic surfactant NP-40 affected the microstructure of polymer latex film and, consequently, its thermal characteristics.