Influence of the tetraalkoxysilane crosslinker on the properties of polysiloxane-based elastomers prepared by the Lewis acid-catalysed Piers-Rubinsztajn reaction
Abstract
We investigate the preparation of polysiloxane-based networks under solvent-free, ambient conditions using the Lewis acid catalysed Piers-Rubinsztajn (PR) reaction of hydride-terminated siloxanes with various tetrafunctional alkoxysilanes (tetraethoxysilane, tetrapropoxysilane, tetra-n-buxoxysilane, tetra-s-butoxysilane, tetra-s-butoxysilane, and tetrakis(2- ethylbutoxy)silane) as crosslinkers. We explore the effects of polysiloxane chain length and crosslinker alkyl group on the rheological performance of the elastomers. By analysing the reaction progress by grazing angle Fourier-transform infrared spectroscopy (FTIR) and determining the rheological properties of the resulting materials, we show that the use of linear or branched alkoxysilanes strongly influences the morphology and properties of these network polymers. We have shown the PR process is can be tailored to reliably produce homogeneous, polysiloxane network materials. This work provides information on the relative rates of network formation under ambient conditions with an emphasis on the impact of crosslinker alkyl chain length. Our results show that electronics and s terics both play critical roles in influencing the the rate of the curing reaction. Crucially, we newly demonstrate the benefit of a having tertiary carbon α to the SiO reaction centre, as is the case for the tetra-s-butoxysilane crosslinker, for delivering exceptionally rapid network cure and a concomitant enhancement in storage modulus of the resultant materials.Citation
Hickman, A. M., Chmel, N., Cameron, N. R., Keddie, D. J. et al. (2021) Influence of the tetraalkoxysilane crosslinker on the properties of polysiloxane-based elastomers prepared by the Lewis acid-catalysed Piers-Rubinsztajn reaction, Polymer Chemistry. https://doi.org/10.1039/D1PY00872BPublisher
Royal Society of ChemistryJournal
Polymer ChemistryAdditional Links
https://pubs.rsc.org/en/Content/ArticleLanding/2021/PY/D1PY00872BType
Journal articleLanguage
enDescription
This is an accepted manuscript of an article published by Royal Society of Chemistry in Polymer Chemistry, available online: https://doi.org/10.1039/D1PY00872B The accepted version of the publication may differ from the final published version.ISSN
1759-9954ae974a485f413a2113503eed53cd6c53
10.1039/D1PY00872B
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