Synthesis and Characterization of Hybrid Core–Shell Systems Based on Molecular Silicasols

Kazakova, V. V.; Zhiltsov, A. S.; Gorbatsevitch, Olga B.; Meshkov, I. B.; Pletneva, M. V.; Демченко, Н. В.; Cherkaev, G. V.; Muzafarov, А. М.

doi:10.1007/s10904-011-9605-4

Cited by 19 publications

(5 citation statements)

References 26 publications

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“…Molecular silicasol particles with γ‐hydroxypropylic, (methoxyacetyl)oxy, and acetoxy surface groups served as fillers. Synthetic strategies and particles surface modifications have been previously described, and the synthetic schemes are shown in Figure . The experimental procedures are described in Supporting Information; infrared (IR) and proton nuclear magnetic resonance ( 1 HNMR) spectra of the particles are shown in Supporting Information Figures S1–S5.…”

Section: Methodsmentioning

confidence: 99%

Polylactide and hybrid silicasol nanoparticle‐based composites

Zhiltsov

Gritsenko

Kazakova

et al. 2015

J of Applied Polymer Sci

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The effects of the chemical nature and size of the hybrid nanoparticle external layer on the structures and properties of polylactide composites are investigated. Polylactide is used as the matrix polymer, and molecular silicasol particles with chydroxypropylic, (methoxyacetyl)oxy, and acetoxy surface groups serve as fillers. A preliminary assessment of the thermodynamic compatibility of polylactide with the surface groups of molecular silicasols is performed. The hydrophilic shells of the silicasols prevent their aggregation in the bulk of the nanocomposite. It shows variations in the chemical structure of the surface layer of the nanoparticles as well as their sizes and concentration make it possible to conduct a controlled change of the characteristics of the composites, particularly to eliminate one of the drawbacks of PLA, the low speed of its crystallization. V C 2015 Wiley Periodicals, Inc. J.Appl. Polym. Sci. 2015, 132, 41894.

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Section: Methodsmentioning

confidence: 99%

Polylactide and hybrid silicasol nanoparticle‐based composites

Zhiltsov

Gritsenko

Kazakova

et al. 2015

J of Applied Polymer Sci

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“…The MQ copolymers with an M:Q ratio of 1:1.5 are most widely used. The versatility of these systems was taken for granted for a long time, and only new discoveries of the composite nature of this complex polymer system enabled their studies to be brought to the standard “structure—properties” paradigm [ 20 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. It was found that the properties of MQ copolymers are determined not only by the ratio of their units but also by the core—shell ratio in each individual macromolecule.…”

Section: Introductionmentioning

confidence: 99%

New Principles of Polymer Composite Preparation. MQ Copolymers as an Active Molecular Filler for Polydimethylsiloxane Rubbers

et al. 2021

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Colorless transparent vulcanizates of silicone elastomers were prepared by mixing the components in a common solvent followed by solvent removal. We studied the correlation between the mechanical behavior of polydimethylsiloxane (PDMS)-rubber compositions prepared using MQ (mono-(M) and tetra-(Q) functional siloxane) copolymers with different ratios of M and Q parts as a molecular filler. The composition and molecular structure of the original rubber, MQ copolymers, and carboxyl-containing PDMS oligomers were also investigated. The simplicity of the preparation of the compositions, high strength and elongation at break, and their variability within a wide range allows us to consider silicone elastomers as a promising alternative to silicone materials prepared by traditional methods.

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“…Based on the presence of particular units, there are MQ, MT, MDT resins, and so on. − The hyperbranched structure of silicone resins allows for various interpretations of their nature. They can be considered core/shell nanoparticles with a cross-linked silica core and a shell of organic groups grafted onto the surface, hyperbranched macromolecules with terminal organic groups, or colloidal nanogels. − They have a dual nature, being both macromolecules and nanoparticles, so even with complete miscibility with the linear polymer, their miscible blends can be considered as molecular composites. , …”

Section: Introductionmentioning

confidence: 99%

Rheology and Miscibility of Linear/Hyperbranched Polydimethylsiloxane Blends and an Abnormal Decrease in Their Viscosity

Ilyin,

Kulichikhin

2023

Macromolecules

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Linear polymers with the same monomer units and different molecular weights form miscible blends considered to be single polymers, but the situation changes if one is hyperbranched. Hyperbranched macromolecules can significantly change the rheology of a linear polymer due to a different flow mechanism and can even lead to the formation of immiscible or partially miscible blends with unusual mechanical properties due to the emulsion state and low droplet–matrix interfacial tension. Blends of hyperbranched polydimethylsiloxane (silicone MT resin, H-PDMS) with similar linear polymers (L-PDMS) of different molecular weights in a concentration range from 20 to 80% have been studied in this work. Laser interferometry of the diffusion zone between H-PDMS and L-PDMS showed their limited miscibility that is improving with decreasing molecular weight of the linear polymer, leading to a decrease in the upper critical solution temperature. The solubility of H-PDMS in L-PDMS is much higher than that of L-PDMS in H-PDMS (20–50% versus 1–2% at 25 °C, depending on the molecular weight of L-PDMS), and H-PDMS emulsifies in L-PDMS but not vice versa. As a result, the partially miscible blends are emulsions of almost pure H-PDMS in a saturated H-PDMS/L-PDMS solution, even at an H-PDMS concentration as high as 80%. The thermorheological behavior of blends was described using an averaged combination of the Arrhenius and Williams–Landel–Ferry equations, allowing for overcoming the large difference in the glass transition temperatures of hyperbranched and linear macromolecules. The viscosity of blends with a higher-molecular-weight L-PDMS has a positive deviation from the log-additivity rule due to macromolecular entanglements, while a decrease in the molecular weight of L-PDMS causes an abnormal drop in viscosities below those of pure polymers. The anomalous decrease in viscosity appears only in a specific temperature range and is explained by mixing a polymer with a high glass transition temperature and high flow activation energy (H-PDMS) with one having lower values of these characteristics (L-PDMS).

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Synthesis and Characterization of Hybrid Core–Shell Systems Based on Molecular Silicasols

Cited by 19 publications

References 26 publications

Polylactide and hybrid silicasol nanoparticle‐based composites

Polylactide and hybrid silicasol nanoparticle‐based composites

New Principles of Polymer Composite Preparation. MQ Copolymers as an Active Molecular Filler for Polydimethylsiloxane Rubbers

Rheology and Miscibility of Linear/Hyperbranched Polydimethylsiloxane Blends and an Abnormal Decrease in Their Viscosity

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