Study of the hydrolysis of TEOS-TMOS mixtures under ultrasound stimulation

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dc.contributor.authorDonatti, D. A.
dc.contributor.authorVollet, D. R.
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:23:53Z
dc.date.available2014-05-20T15:23:53Z
dc.date.issued1996-10-01
dc.description.abstractPure and mixed tetramethoxysilane (TMOS) and tetraethoxysilane (TEOS) were hydrolyzed at 35 degrees C, using oxalic acid as a catalyst and ultrasound stimulation. The hydrolysis reaction was carried out in a specially designed device, in which a heat flow steady state, between the ultrasound source and an external thermostatic bath, was maintained, in the absence of reactions. The exothermic hydrolysis causes a time dependent thermal peak. An induction time is apparent in pure TEOS before the hydrolysis peaks starts, which has been explained by the initial immiscibility gap of the TEOS-water system. The induction time was found to be approximately of the same magnitude as in the HCl catalyzed hydrolysis, in spite of the uncertainty accompanying the peak definition. No induction period is apparent in pure TMOS, so that the hydrolysis starts with its maximum rate. Two independent thermal peaks in the mixed TMOS-TEOS samples were found, both associated to the respective hydrolyses of the pure component. The induction time for the TEOS hydrolysis is decreased as more alcohol (and silanol) is produced in the earlier TMOS hydrolysis. This effect is explained by improvement of homogenization by alcohol.en
dc.description.affiliationUNESP,DEPT FIS,CAMPUS RIO CLARO,CX P 178,BR-13500970 RIO CLARO,SP,BRAZIL
dc.description.affiliationUnespUNESP,DEPT FIS,CAMPUS RIO CLARO,CX P 178,BR-13500970 RIO CLARO,SP,BRAZIL
dc.format.extent301-304
dc.identifierhttp://dx.doi.org/10.1016/S0022-3093(96)00617-5
dc.identifier.citationJournal of Non-crystalline Solids. Amsterdam: Elsevier B.V., v. 204, n. 3, p. 301-304, 1996.
dc.identifier.doi10.1016/S0022-3093(96)00617-5
dc.identifier.issn0022-3093
dc.identifier.lattes3538107401166553
dc.identifier.lattes2661573794233385
dc.identifier.urihttp://hdl.handle.net/11449/34583
dc.identifier.wosWOS:A1996VV24500012
dc.language.isoeng
dc.publisherElsevier B.V.
dc.relation.ispartofJournal of Non-Crystalline Solids
dc.relation.ispartofjcr2.488
dc.relation.ispartofsjr0,722
dc.rights.accessRightsAcesso aberto
dc.sourceWeb of Science
dc.titleStudy of the hydrolysis of TEOS-TMOS mixtures under ultrasound stimulationen
dc.typeCarta
dcterms.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dcterms.rightsHolderElsevier B.V.
unesp.author.lattes3538107401166553
unesp.author.lattes2661573794233385
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Geociências e Ciências Exatas, Rio Claropt

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Artigos - Física - IGCE