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Open AccessArticle

Synthesis, Characterization and Microstructure of New Liquid Poly(methylhydrosiloxanes) Containing Branching Units SiO4/2

1
Textile Research Institute, Brzezińska Str. 5/15, 92-103 Łódź, Poland
2
The Institute of Security Technologies “MORATEX”, Marii Skłodowskiej-Curie Str. 3, 90-505 Łódź, Poland
3
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza Str. 112, 90-363 Łódź, Poland
*
Author to whom correspondence should be addressed.
Polymers 2018, 10(5), 484; https://doi.org/10.3390/polym10050484
Received: 28 March 2018 / Revised: 25 April 2018 / Accepted: 25 April 2018 / Published: 28 April 2018
(This article belongs to the Special Issue Siloxane-Based Polymers)
Six liquid branched poly(methylhydrosiloxanes) of new random structures (PMHS-Q), containing quadruple branching units SiO4/2 (Q), both MeHSiO (DH) and Me2SiO (D) chain building units (or only mers MeHSiO), and terminal groups Me3SiO0.5 (M) were prepared by a hydrolytic polycondensation method of appropriate organic chlorosilanes and tetraethyl ortosilicate (TEOS), in diethyl ether medium at temperature below 0 °C. Volatile low molecular weight siloxanes were removed by a vacuum distillation at 150–155 °C. Yields of PMHS-Q reached from 55–69 wt%. Their dynamic viscosities were measured in the Brookfield HBDV+IIcP cone-plate viscometer and ranged from 10.7–13.1 cP. Molecular weights (MW) of PMHS-Q (Mn = 2440–6310 g/mol, Mw = 5750–10,350 g/mol) and polydispersities of MW (Mw/Mn = 2.0–2.8) were determined by a size exclusion chromatography (SEC). All polymers were characterized by FTIR, 1H- and 29Si-NMR, and an elemental analysis. A microstructure of siloxane chains was proposed on a basis of 29Si-NMR results and compared with literature data. View Full-Text
Keywords: hyperbranched poly(methylhydrosiloxanes); hydrolytic polycondensation; 29Si-NMR; topology of polysiloxane chains hyperbranched poly(methylhydrosiloxanes); hydrolytic polycondensation; 29Si-NMR; topology of polysiloxane chains
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Chruściel, J.J.; Fejdyś, M.; Fortuniak, W. Synthesis, Characterization and Microstructure of New Liquid Poly(methylhydrosiloxanes) Containing Branching Units SiO4/2. Polymers 2018, 10, 484.

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