Condensation of all-cis-tetraphenylcyclotetrasiloxanetetraol in ammonia: new method for preparation of ladder-like polyphenylsilsesquioxanes

Анисимов, А. А.; Polshchikova, N. V.; Vysochinskaya, Yuliya S.; Zader, P. A.; Никифорова, Г. Г.; Peregudov, Аlexander S.; Бузин, М. И.; Shchegolikhina, Olga I.; Muzafarov, А. М.

doi:10.1016/j.mencom.2019.07.022

Cited by 20 publications

(10 citation statements)

References 26 publications

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“…Indeed, both samples show comparable diffractograms characterized by a broad hump centered at 23° 2θ, typically observed in amorphous silica‐based solids (Figure , b–d). Probably, the organization of POSS cages in the PSQ chains is asymmetric and irregular and the presence of ladder‐like domains can be excluded …”

Section: Resultsmentioning

confidence: 99%

A Luminescent Polysilsesquioxane Obtained by Self‐Condensation of Anionic Polyhedral Oligomeric Silsequioxanes (POSS) and Europium(III) Ions

et al. 2020

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The self-condensation reaction of an anionic completely condensed polyhedral oligomeric silsequioxane (POSS) in the presence of different Eu 3 + loadings generated an amorphous polysilsequioxane. The synthesis involves self-condensation of POSS units and Eu 3 + ions and can be carried out at room temperature in a mild acid solution (pH 5.5), followed by simple solvent evaporation under gentle conditions (80°C). The materials exhibit good chemical integrity, appreciable luminescent properties, and their emission intensity increases by ca. 250 times after inclusion of 1,10-phenanthroline groups in the structure. Furthermore, the final materials showed a very limited photodegradation of ca. 3 % after 1 h of light irradiation. These properties make these samples suitable for applications as sensors and light-emitting components for luminescent devices.

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Section: Resultsmentioning

confidence: 99%

A Luminescent Polysilsesquioxane Obtained by Self‐Condensation of Anionic Polyhedral Oligomeric Silsequioxanes (POSS) and Europium(III) Ions

et al. 2020

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“…The XRD patterns of our samples show two diffraction maxima, which are described to be characteristic of a ladderlike structure. ,− The first reflection at lower angles is associated with the chain-to-chain distance ( d 1 ) between the siloxane backbones and correlates with the packing density of the network. , The second reflection is related to the average thickness of the double-stranded siloxane backbone ( d 2 ) (Figure , Table ). Both samples reveal similar d 2 values (0.45 nm), which is a known phenomenon in ladderlike structures. ,, The chain-to-chain distance d 1 shows a shift to lower 2θ values within the consolidation process.…”

Section: Results and Discussionmentioning

confidence: 88%

“…The restricted chain mobility and the bulky aromatic groups lead to a larger chain-to-chain distance (1.15 nm) and a lower packing density close to the values described in the literature for ladderlike polyphenylsilsesquioxanes. 48,52 It becomes clear that the condensation process does not only occur intramolecularly in the ladder-type structure but also intermolecularly. A thermal-induced exclusively intramolecular cross-linking would lead to a more perfect ladder-type polymer structure, which still can be molten or softened, like a polymer chain.…”

Section: %mentioning

confidence: 99%

Thermoplastic Silsesquioxane Hybrid Polymers with a Local Ladder-Type Structure

Pohl

Janka

Füglein³

et al. 2021

Macromolecules

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Organosilsesquioxane hybrid materials are an important class of functional materials due to their tailorable functions and high thermal and optical stability. Recently, several studies showed that phenyl-substituted trialkoxysilanes can be converted into reversibly melting gels by applying hydrolysis and condensation reactions. We studied the underlying mechanisms of their formation and the final structure in detail by a combination of various spectroscopic techniques, thermal analysis, size exclusion chromatography, and X-ray diffraction. Our investigations reveal that local ladder-type silsesquioxanes with a defect-rich structure are formed in a first hydrolysis and condensation step. The partial presence of stable −OH and methoxy groups attached to the aryl-substituted silicon atoms in the ladderlike polymer explains their thermoplastic behavior. Heating above a particular consolidation temperature leads to further condensation reactions of the residual groups as well as a structural reorientation of the ladder-type polymers. The final materials are hard and cross-linked hybrid glasses with thermal stability higher than 400 °C and high optical transparency.

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“…Previously, we demonstrated the effectiveness of a similar approach to the condensation of phenylsilanols. − Here, we report our research on water-initiated anionic polymerization of hexamethylcyclotrisiloxane (D 3 Me2 ).…”

Section: Introductionmentioning

confidence: 97%

Low Dispersity Telechelic Polydimethylsiloxanes Synthesized in Ammonia Medium

Minyaylo

Temnikov

Анисимов

et al. 2022

ACS Appl. Polym. Mater.

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The polymerization of hexamethylcyclotrisiloxane (D 3 Me2 ) in liquid ammonia using water as an initiator has been studied. These polymers are of practical importance for a wide range of applications in the silicone industry. The effect of factors such as temperature, reaction time, and concentration of reactants on the polymerization process was evaluated. As a result, an environmentally friendly procedure for the preparation of narrowly dispersed telechelic polydimethylsiloxanes (Mn = 8.0 kDa, PDI = 1.11) with a monomer conversion of up to 98% was developed. The possibility of scaling up the process and recycling of ammonia was shown.

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Condensation of all-cis-tetraphenylcyclotetrasiloxanetetraol in ammonia: new method for preparation of ladder-like polyphenylsilsesquioxanes

Cited by 20 publications

References 26 publications

A Luminescent Polysilsesquioxane Obtained by Self‐Condensation of Anionic Polyhedral Oligomeric Silsequioxanes (POSS) and Europium(III) Ions

A Luminescent Polysilsesquioxane Obtained by Self‐Condensation of Anionic Polyhedral Oligomeric Silsequioxanes (POSS) and Europium(III) Ions

Thermoplastic Silsesquioxane Hybrid Polymers with a Local Ladder-Type Structure

Low Dispersity Telechelic Polydimethylsiloxanes Synthesized in Ammonia Medium

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