, Volume 291, Issue 5, pp 1181-1190
Date: 10 Nov 2012

Preparation and characterization of film-forming raspberry-like polymer/silica nanocomposites via soap-free emulsion polymerization and the sol–gel process

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Herein, we report on the synthesis of film-forming poly(styrene-co-butyl acrylate-co-acrylic acid)/SiO2 [P(St-BA-AA)/SiO2] nanocomposites by in situ formation of SiO2 nanoparticles from TEOS via sol–gel process in the presence of poly(acrylic acid) (PAA)-functionalized poly(styrene-co-butyl acrylate) [P(St-BA)] particles fabricated by soap-free emulsion polymerization. The formed silica particles could be absorbed by polyacrylate chains on the surface of PAA-functionalized P(St-BA) particles; thus, raspberry-like polymer/silica nanocomposites would be obtained. Transmission electron microscopy, Fourier transform infrared spectroscopy, attenuated total reflectance infrared spectrum, ultraviolet–visible transmittance spectra, and thermogravimetric analysis were used to characterize the resulting composites. The results showed that the hybrid polymer/silica had a raspberry-like structure with silica nanoparticles anchored on the surface of polymer microspheres. The thermal, fire retardant, and mechanical properties and water resistance of the film were improved by incorporating silica nanoparticles, while the optical transmittance was seldom affected due to nanosized silica particles uniformly dispersed in the film.


Film-forming polymer/silica nanocomposites with raspberry-like morphology have been successfully prepared via soap-free emulsion polymerization followed by the sol–gel process. The number and the size of SiO2 particles coated on the surface of polymer particles can be adjusted by the amounts of TEOS and ammonia. After the film formation of polymer/silica nanocomposites, silica nanoparticles are homogeneously dispersed within the film without aggregation.