Phase state and rheology of organosilicon nanocomposites with functionalized hyperbranched nanoparticles

The phase equilibrium in a system of linear polydimethylsiloxane–functionalized nanoparticles 1.2–2.2 nm in size with a core made of hyperbranched silica and a periphery of decyl groups has been studied by laser interferometry method. Phase diagrams of the studied systems fit the amorphous phase equilibrium with UCST increasing with the nanoparticle size. The mixtures present nanoparticle solutions in the linear polymer or emulsions of a saturated solution of one component in a saturated solution of other component depending on the components ratio. Dilute, concentrated, or highly concentrated dispersions show individual features of the rheological behavior. For each colloid chemical and phase states of mixtures, the viscosity and viscoelastic properties have been investigated in a wide temperature range. The obtained results have been compared with the previous data for mixtures of decylated nanoparticles and polyisobutylene.