Effect of organoclay reinforced acrylate latex particles on the cement paste performance

In this study, to investigate the effects of organoclay nanoparticles on the properties of latexes as a cement additive, two kinds of acrylate latexes, poly(styrene-co-butyl acrylate-co-metacrylic acid) (PSBAMA) and poly(styrene-co-2ethylhexyl acrylate-co-metacrylic acid) (PSEHAMA), and their nano composites with organoclay nanoparticles, Cloisite 15A, were synthesized via in-situ emulsion polymerization. Obtained results from laser light scattering (LLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and mechanical test showed good dispersion of Cloisite15A (C15A) nanoparticles in the polymer matrix. Afterward, synthesized latexes with various amounts of organoclay nanoparticles were added to cement paste to investigate its performance. The mechanical test results showed that although neat latexes improved the flexural strength of the hydrated cement paste (up to 28.89%), existence of the organoclay nanoparticles in the structure of the latexes improved the flexural strength further (up to 47%). Furthermore, despite the reduction in compressive strength of the cement paste by adding neat latexes, existence of organoclay nanoparticles in the structure of latex almost eliminated this drawback of using latexes in cement paste. In addition, the results showed that the incorporation of 5 wt% emulsion particles containing 1 wt% Cloisite15A (C15A) considerably decreased the water absorption of the paste. Studies by X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectroscopy indicated that the degree of hydration of the paste was increased in the presence of emulsion particles. Existence of neat and composite latex particles also changed the morphology of the cement, which was confirmed by scanning electron microscopy (SEM) results.