The role of vinyl terminated silanes for producing highly concentrated polystyrene slurries in a single step process
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ORIGINAL CONTRIBUTION
The role of vinyl terminated silanes for producing highly concentrated polystyrene slurries in a single step process Daniel López-Pedrajas 1 & Ana M. Borreguero 1 & F. Javier Ramos 1 & Manuel Carmona 1 & Juan Francisco Rodríguez 1 Received: 10 April 2020 / Revised: 14 August 2020 / Accepted: 16 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Slurries with low viscosity and polystyrene (PS) nanoparticle concentration up to 52 wt.% have been synthesized in one-step process with no waste generation, by suspension polymerization and optimizing the concentration of dispersants (sodium dodecyl sulfate, SDS, and the cosurfactant, CS). The CS was manufactured in situ from tetraethyl orthosilicate (TEOS) and vinyltriethoxysilane (VTES). The incorporation of the CS on the PS polymer was confirmed by FT-IR, EDS, and TGA, observing the functionalization of PS nanoparticles with SiOH. Morphology and particle size of the dispersed solid, together with viscosity and stability of the polystyrene slurries (PSSs), were analyzed, finding an abrupt reduction of the viscosity for PSSs by combining SDS and CS. Addition of SDS and CS (3.0 and 1.5 wt.%, respectively) allowed to produce PSSs with improved stability (ζ = − 48.5 mV after 1 year), low viscosity (20.5 mPa·s at 25 °C), and Newtonian behavior, containing up to 40.0 wt.% of single-spherical PS nanoparticles (< 100 nm). Keywords Single process . Nano-slurry . Polystyrene nanoparticles . Sodium dodecyl sulfate (SDS) . Vinyl terminate silanes . Silica functionalization
Introduction A slurry is a fluid formed by a stable dispersion of a solid into a liquid (commonly water or glycerol). Slurries are habitually made by dispersing either micro or nanoparticles in the media by means of dispersants and, commonly, with the help of mechanical stirring or sonication. This kind of material can flow not only under the effect of gravity, but can also be pumped. Therefore, slurries facilitate the manipulation of bulk solids and, depending on the nature of the dispersed particles, they can be applied in many different fields [1–3], such as mining [4], excavation [5, 6], construction [7], coating/ plating [8], sealing [9, 10], ceramics [11], and thermal energy storage [12–14]. One of the key parameters, which determine the properties of a slurry, is the size of the dispersed solid particles. Polymer slurries formed by micro-particles have been more explored * Juan Francisco Rodríguez [email protected] 1
Department of Chemical Engineering, Institute of Chemical and Environmental Technology, University of Castilla-La Mancha, Avda. De Camilo Jose Cela s/n, 13071 Ciudad Real, Spain
than nanoparticle-based ones, since obtaining micro-particle size is easier. For instance, Ugelstad et al. [15] reported the first approach of a slurry made of polystyrene (PS) microparticles by emulsion polymerization using an emulsifier mixture of anionic emulsifier and fatty alcohol. Unfortunately, the average size of dispersed particles in that slurry wa
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