Synthesis of nano CaCO ₃ /acrylic co‐polymer latex composites for interior decorative paints

CaCO ₃ nanoparticles were synthesised in patented solution spray reactor system using non‐ionic Tween‐80 surfactant as template. Design of solution spray reactor permits the intimate thin film contact between the highly atomized precursor and precipitant solutions to control the CaCO ₃ size in 25–90 nm range. CaCO ₃ nanoparticles were surface modified with γ‐methacryloxypropyltrimethoxysilane (GMPTS) in order to improve the compatibility with polymer matrix. CaCO ₃ /acrylic co‐polymer latex nanocomposites were prepared by in situ emulsion polymerization with 0.5‐2.5 wt % loadings of nanoCaCO ₃ . Functional group, surface modification, crystal phase, size and morphology of CaCO ₃ nanoparticles were determined by their FTIR, XRD and FESEM analysis. DSC and TGA analysis was performed to establish the rise in thermal stability of latex nanocomposites due to inclusion of nanoCaCO ₃ , while its ultrafine dispersion in polymer matrix was confirmed by FESEM analysis of latex nanocomposite films. Interior waterborne decorative paints were formulated using CaCO ₃ /acrylic co‐polymer latex nanocomposites as binder. Overall three fold rise in performance of latex nanocomposite paint over that of clear latex paint in terms of wet scrub, mar and stain resistance, cross cut adhesion and pencil hardness was observed which implies commercial viability of use of surface modified nanoCaCO ₃ . POLYM. COMPOS., 39:1350–1360, 2018. © 2016 Society of Plastics Engineers