New Condensation Polymer Precursors Containing Consecutive Silicon Atoms-Decaisopropoxycyclopentasilane and Dodecaethoxyneopentasilane-And Their Sol⁻Gel Polymerization.

Sung Jin Park,Myong Euy Lee,Sangdeok Shim,Hyeon Mo Cho

doi:10.3390/polym11050841

Sung Jin Park, Myong Euy Lee + Show 2 more

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https://doi.org/10.3390/polym11050841

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Journal: Polymers	Publication Date: May 9, 2019
Citations: 1	License type: CC BY 4.0

Affiliation: Yonsei University, Sunchon National University

Abstract

The sol–gel polymerization of alkoxysilanes is a convenient and widely used method for the synthesis of silicon polymers and silicon–organic composites. The development of new sol–gel precursors is very important for obtaining new types of sol–gel products. New condensation polymer precursors containing consecutive silicon atoms—decaisopropoxycyclopentasilane (CPS) and dodecaethoxyneopentasilane (NPS)—were synthesized for the preparation of polysilane–polysiloxane material. The CPS and NPS xerogels were prepared by the sol–gel polymerization of CPS and NPS under three reaction conditions (acidic, basic and neutral). The CPS and NPS xerogels were characterized using N2 physisorption measurements (Brunauer–Emmett–Teller; BET and Brunauer-Joyner-Halenda; BJH), solid-state CP/MAS (cross-polarization/magic angle spinning) NMRs (nuclear magnetic resonances), TEM, and SEM. Their porosity and morphology were strongly affected by the structure of the precursors, and partial oxidative cleavage of Si-Si bonds occurred during the sol–gel process. The new condensation polymer precursors are expected to expand the choice of approaches for new polysilane–polysiloxane.

Highlights

Brunauer-Joyner-Halenda; BJH), solid-state CP/MAS NMRs, TEM, and SEM. Their porosity and morphology were strongly affected by the structure of the precursors, and partial oxidative cleavage of Si-Si bonds occurred during the sol–gel process
The new condensation polymer precursors are expected to expand the choice of approaches for new polysilane–polysiloxane
Sol–gel polymerization of multialkoxysilanes is a convenient method for the synthesis of silicon polymers and silicon–organic composites under mild conditions [1–9]

Summary

Introduction

Sol–gel polymerization of multialkoxysilanes is a convenient method for the synthesis of silicon polymers and silicon–organic composites under mild conditions [1–9]. Our group found interesting reactivities of peralkoxy-, perchlorocyclopentasilane, and perchloroneopentasilane: (i) Si–Si bond breaking of a soluble polymer synthesized from decaethoxycyclopentasilane with methyltrimethoxysilane occurred even at one minute-baking conditions (200 ◦ C) [14], while a polymer obtained from hexaethoxyhexamethylcyclohexasilane with methyltrimethoxysilane was thermally stable; (ii) adding a secondary amine into. [14], while a polymer obtained from hexaethoxyhexamethylcyclohexasilane with methyltrimethoxysilane was thermally stable; ii) adding decachlorocyclopentasilane and dodecachloroneopentasilane [15] induced Si–Si bond cleavages [16–20]. The interesting cleavage reactivity of the consecutive silicon bonds in the oligosilanes and. The interesting cleavage reactivity of the consecutive silicon bondsthe in lack of study onand thethe sol–gel of the peralkoxyoligosilanes prompted us to study their sol–gel the oligosilanes lack ofprocess study on sol–gel process of peralkoxyoligosilanes prompted us to reaction

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