Rheological properties of nonfunctional derivatives of hyperbranched polycarbosilanes

Sheremetyeva, Natalia A.; Vasiliev, V. G.; Папков, В. С.; Pak, G. G.; Kramarenko, Elena Yu.; Muzafarov, А. М.

doi:10.1007/s11172-015-1130-0

Cited by 7 publications

(4 citation statements)

References 28 publications

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“…Molecular mass of the polymer determined by GPC is equal to 64 000, and according to DLS measurements it is equal to 69 900 [26]. In the temperature range of 20-80 °C the PCS-dodec melt behaves as a Newtonian liquid, with its viscosity equal to 40 Pa • s at 20 °C, and the activation energy is equal to 43 kJ mol −1 [26].…”

Section: Methodsmentioning

confidence: 99%

“…The branching degree after blocking is equal to unity. The synthesis details are given in [26]. HB polymers were obtained through the preparation of the original hyperbranched polymethyldiundecenylcarbosilane matrix by onestep synthesis from the corresponding AB 2 -type monomer by polyaddition reaction in the presence of a platinum catalyst, followed by blocking of the terminal double bonds with a methyldodecylsilane modifying agent via hydrosilylation reaction.…”

Section: Methodsmentioning

confidence: 99%

“…Recent study of the rheological properties of melts of non-functional HB polycarbosilane polymers has shown that unlike melts of linear polymers, investigated HB systems are Newtonian fluids, whose viscosity and the activation energy of viscous flow depend strongly on the molecular parameters and regularity of the molecular structure [26] and thus, can be varied in a wide range.…”

Section: Introductionmentioning

confidence: 99%

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Magnetorheological fluids based on a hyperbranched polycarbosilane matrix and iron microparticles

Vasiliev

Sheremetyeva

Бузин

et al. 2016

Smart Mater. Struct.

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Magnetorheological fluids (MFs) based on hyperbranched polycarbosilanes as a carrier medium and micron-sized carbonyl iron particles as filler have been synthesized for the first time. Their magnetorheological (MR) behavior has been studied in steady-state flow regime and under dynamic torsion oscillations on a commercial rheometer. At zero magnetic field, in spite of a rather high molecular mass, the hyperbranched polymers as well as their magnetic compositions with up to 72 mass% of magnetic filler demonstrate Newtonian behavior, and their viscosity considerably increases with magnetic filler content. In magnetic fields MFs show a huge MR response. Namely, in steady-state flow experiments a five orders of magnitude increase in viscosity was observed accompanied by magnetic-field-induced well-pronounced non-Newtonian behavior and a non-zero yield stress. Dynamic experiments demonstrate the transition from liquid-like to solid-like behavior of MFs with a large increase in both the storage and loss moduli under application of a magnetic field. In magnetic fields, the rheological behavior of the obtained MF resembles that of soft MR elastomers being mainly determined by the magnetic particle network formed due to magnetic interactions. In particular, like MR elastomers the MFs exhibit the Payne effect, i.e. dependence of the dynamic modulus on the strain amplitude.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetorheological fluids based on a hyperbranched polycarbosilane matrix and iron microparticles

Vasiliev

Sheremetyeva

Бузин

et al. 2016

Smart Mater. Struct.

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“…Among a wide variety of chemical compositions of dendrimers, it is worth noting, especially for the class of dendrimers, in which branching occurs due to valence in silicon atoms, namely, carbosilane and siloxane dendrimers [25][26][27], that these dendrimers represent good model systems to study pure effect of tree-like architectures, since they do not contain any groups with specific interactions like, for instance, hydrogen bonding or electrostatic interactions, which contribute a lot into the intermolecular interactions. To date, a large amount of experimental material has been collected on the behavior of polybutylcarbosilane dendrimers in bulk, depending on core and branching functionalities [20,26,[28][29][30][31][32][33][34][35][36][37]. Two fascinating phenomena observed experimentally should be highlighted.…”

Section: Introductionmentioning

confidence: 99%

Structure and Mechanical Response of Polybutylcarbosilane Dendrimers Confined in a Flat Slit: Effect of Molecular Architecture and Generation Number

Kurbatov,

Balabaev,

Litvin

et al. 2023

Polymers

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Due to the absence of specific interactions, carbosilane dendrimers are ideal models to study the effect of a hyperbranched regular structure on the molecular response to external influences. In this work, we have studied the conformational behavior of single polybutylcarbosilane dendrimers under confinement between impermeable flat surfaces using atomistic molecular dynamics simulations. Dendrimers of different generations belonging to two homologous series with a tetra-functional core and three- and four-functional branches were simulated. The analysis of the dependence of the internal energy of the dendrimers on the wall distance allowed us to determine the critical degree of compression at which the dendrimers are able to change their shape without energy loss. The effects of generation number and branching functionality on the number of wall contacts, density distribution and shape changes were elucidated. It was found that for high generation dendrimers, the inner layers are not accessible for external interaction. It was shown that the excess stresses occurring at high compressions are concentrated in the structural center of the dendrimer. The nature of the elastic response, which is strongly nonlinear, was analyzed at different compressions depending on the dendrimer architecture and generation. We believe that our results are useful for further studies of dendrimer films under compression and can also serve as a basis for developing model concepts to describe the dynamics of dendrimer melts.

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Rheological properties of sulfur-containing hyperbranched polycarbosilanes and related magnetic compositions

et al. 2016

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Rheological properties of nonfunctional derivatives of hyperbranched polycarbosilanes

Cited by 7 publications

References 28 publications

Magnetorheological fluids based on a hyperbranched polycarbosilane matrix and iron microparticles

Magnetorheological fluids based on a hyperbranched polycarbosilane matrix and iron microparticles

Structure and Mechanical Response of Polybutylcarbosilane Dendrimers Confined in a Flat Slit: Effect of Molecular Architecture and Generation Number

Rheological properties of sulfur-containing hyperbranched polycarbosilanes and related magnetic compositions

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