Synthesis and study of the properties of the homologous series of polyallylcarbosilane dendrimers and their nonfunctional analogs

Татаринова, Е. А.; Rebrov, E. A.; Myakushev, V. D.; Meshkov, I. B.; Демченко, Н. В.; Bystrova, A. V.; Лебедева, О. В.; Muzafarov, А. М.

doi:10.1007/s11172-005-0159-x

Cited by 50 publications

(42 citation statements)

References 30 publications

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“…After substi tution of the partial specific volume for co PPGs, we arrive at [η] sph ≈ 1.3 cm 3 /g. This estimate is somewhat smaller than the intrinsic viscosity for the lowest molecular mass PPG sample ( [38][39][40] rather than for hyperbranched polymers. For the latter polymers, [η]/[η] sph is usually above 1-5 [17].…”

Section: R 3 Geh : Net 3 or R 3 Gehmentioning

confidence: 76%

Structural and conformational properties of hyperbranched copolymers based on perfluorinated germanium hydrides

et al. 2012

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Two series of hyperbranched copolymers based on perfluorinated germanium hydrides of various topological structures are studied in dilute chloroform solutions by the methods of molecular hydrodynamics and optics. The first series is composed of copolymers with various molecular masses (from 2.3 × 10 4 to 31 × 10 4 ) that contain rigid linear chains between branching points and various amounts of branching points in cascades of the dendritic fragment, while the second series is comprised of copolymers that, at close branch ing degrees, on average, are characterized by a looser structure owing to a large amount of linear units at the periphery of macromolecules with M = (2.5 × 10 4 )-(23 × 10 4 ). Macromolecules of the studied polymers have compact dimensions and a high density of the polymer substance; their shape asymmetry is low. In terms of these characteristics, they approach dendrimers. At a fixed molecular mass, the copolymers with a loose structure have higher dimensions of macromolecules and higher intrinsic viscosities.

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Section: R 3 Geh : Net 3 or R 3 Gehmentioning

confidence: 76%

Structural and conformational properties of hyperbranched copolymers based on perfluorinated germanium hydrides

et al. 2012

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“…7 Samples of carbosilane dendrimers of the sixth genera tion with allyl groups (М = 32013.7) were prepared at the N. S. Enikolopov Institute of Synthetic Polymer Materials, Russian Academy of Sciences using the known procedure. 18 The Pt cata lyst PC072 (Aldrich) was used. All reactions were carried out under argon.…”

Section: Methodsmentioning

confidence: 99%

Multiarm star-like polydimethylsiloxanes based on dendrimers of the sixth generation

et al. 2010

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A series of star like 128 arm polydimethylsiloxanes was synthesized by the anionic poly merization of hexamethylcyclotrisiloxane using the polylithium initiator, which was obtained from the carbosilane dendrimer of the sixth generation. The measured values of molecular weights and intrinsic viscosity made it possible to characterize the samples prepared as dense globular macromolecules. The behavior of the synthesized multiarm stars at the water-air interface was studied, and the cross section surface areas of the macromolecules were calculat ed. A comparison of the obtained sizes with the calculated values suggests some deformation of the dendrite core due to the interaction of the arms with the water surface.Synthesis and investigation of the properties of nano sized structurally ordered macromolecules is an urgent area of modern chemistry. Studies of star like polymer forms have been intensified during recent decade. Such polymers characterized by the presence of several linear oligomeric arms connected with one end on the branching center have several specific features compared to linear analogs with the same molecular weight. Polymer stars having three to four arms connected on one center were synthesized and studied rather long ago. At the early stag es of studying these polymers, mainly decreased viscosi ties of melts and solutions compared to linear analogs of the molecular weight attracted attention of researchers. This property allowed their use as the corresponding addi tives. In addition, they are better processed and useful in composition of coatings to improve a combination of hard ness and flexibility characteristics. The study 1 of the rheo logical properties explained these specific features by the fact that the relaxation time of polymer chains fixed by one end was considerably longer than that of analogous linear polymers. An increase in the number of arms (f ) in a star like structure noticeably changed the behavior of the macromolecule and, beginning from some value of f, the properties changed qualitatively: the transition to so called "multiarm" structures characterized by high density of units in the branching center was observed. Star like polymers with the number of arms f ≤ 32 behave as classi cal liquids at all concentrations in solutions, whereas with the further increase in the number of arms the behavior of multiarm polymers differs entirely from that of normal liquids and approaches the behavior of solid spheres. 2 In this case, coefficient α in the Mark-Kuhn-Houwink equation 3 changes from 0.6-0.7 corresponding to the ball like conformation of the polymer to 0.15-0.06, which characterizes polymers as rigid spherical objects.Thus, there is some critical number of arms and, cor respondingly, some density of the structure, at which the properties "jump" from classical polymeric properties. We earlier 4 synthesized a series of star like polydimethylsilox anes (PDMS) with 12, 14, 16, and 48 arms. It was shown that already in this range an increase in the number of arms of the star like...

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“…Many publications concern systematic research into the effect of the chemical structures of the initial components containing various substituents-for example, fluorine, allyl, undecyl, hydroxyl, and mesogenic groups-and the number of generations on the architecture of dendrimers and their ordering, phase state, rheology, and mobilities of charge carriers [222,[223][224][225][226][227][228][229][230][231][232][233][234].…”

Section: Dendrimersmentioning

confidence: 99%

Achievements in polycondensation and condensation polymers

Sapozhnikov

Vygodskii

2015

Polym. Sci. Ser. B

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Synthesis and study of the properties of the homologous series of polyallylcarbosilane dendrimers and their nonfunctional analogs

Cited by 50 publications

References 30 publications

Structural and conformational properties of hyperbranched copolymers based on perfluorinated germanium hydrides

Structural and conformational properties of hyperbranched copolymers based on perfluorinated germanium hydrides

Multiarm star-like polydimethylsiloxanes based on dendrimers of the sixth generation

Achievements in polycondensation and condensation polymers

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