Synthesis and Properties of Homologous Series of Polyallylcarbosilane Dendrimers with Dense Macromolecular Structure

Abstract

Summary: Synthesis of the six generations of polyallylcarbosilane dendrimers with tetrafunctional branching center and tetrafunctional base reagent is reported. Obtained dendrimers are compared to carbosilane dendrimers with less dense molecular structure synthesized before. Densification of the dendrimer structure alters some basic dendrimer properties as well as their dependence on generation.

Synthesis of Carbosilane Dendrimers with 2-Phenylethyl End Groups and Influence of Generation Number on Glass Transition Temperature of PS-based Composites

“…All dendrimers undergo devitrification in a fairly narrow temperature range. Numerous literature data indicate that the glass transition temperature of carbosilane dendrimers of the same homologous series depends on the outer layer density (molecular mobility of the structural units) [1,9,11,13,14,20,36,37]. Thus increasing its value by seven degrees on going from the first to the sixth generation is an expected result.…”

“…Thus increasing its value by seven degrees on going from the first to the sixth generation is an expected result. Our previous findings revealed that the glass transition temperature of carbosilane dendrimers increases only up to the fifth generation and then remains stable [1,37], because the dendrimer molecular structure becomes much more compact adopting a globular shape. Figure 5 shows the concentration dependencies of the glass transition temperature changes for the studied composites (T gc ) in comparison with the glass transition temperature of the matrix polymer T PS .…”

From the discovery of sodiumoxyorganoalkoxysilanes to the organosilicon dendrimers and back

“…Their application in process of synthesis of functional metalsiloxanes was always in mind but only recently they have been used for the preparation of functional metalosiloxane oligomers 54,55 (Fig. 21).…”

Hybrid organo‐inorganic globular nanospecies: Transition from macromolecule to particle

“…For example, it is known that as molecular structure becomes denser, the notable increase in density of carbosilane dendrimer occurs. While in the case of 3 × 3 and 4 × 3 systems the density does not depend on a number of generations, more dense system 4 × 4 exhibits the linear dependence of the density value on a number of generations 19. It is obvious that the distinctive quantity‐to‐quality transition may affect some other properties of the species as well.…”