In Situ synthesis of poly(styrene–butylacrylate–acrylic acid) latex/barium sulfate nanocomposite and evaluation of their film properties

Barium sulfate nanocrystals of average 40 nm sizes were prepared by the micellar solution spray process. The influences of atomized impingement flow on nanoparticle formation and stabilization were inspected on the basis of Fourier transform infrared (FTIR), X‐ray diffraction, and transmission electron microscopy analysis. Poly(styrene–butylacrylate–acrylic acid) (PSBA) nanocomposites were synthesized by in situ copolymerization in the presence of 0.5–2.5% BaSO₄ nanoparticles. FTIR and atomic force microscopy analysis confirmed the uniform dispersion of 2% or less nano‐BaSO₄ within the PSBA matrix. The strength of interfacial adhesion between the nanoparticle and copolymer was examined on the basis of hydroscopicity, differential scanning calorimetry, thermogravimetric analysis, and universal testing machine analysis of nanocomposite film. The glass transition and thermal decomposition temperatures of PSBA latex were shifted toward higher temperatures by the restriction of nano‐BaSO₄ on its segmental and long‐range chain mobility. The well‐dispersed nano‐BaSO₄, with a larger fraction of immobilized copolymer on the pigment surface, improves the scratch and abrasion resistance, decreases the water uptake, and increases the tensile strength and elongation at break of the latex film within the specific loading. Thus, fabricating the PSBA/BaSO₄ nanocomposite presents an effective approach for development of latex coatings with enhanced performance. POLYM. COMPOS., 34:1670–1681, 2013. © 2013 Society of Plastics Engineers