Inorganic-Organic Sol-Gel Derived Hybrid Materials as Abrasion Resistant Coatings

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dc.contributor.authorLi, Chenghongen
dc.contributor.committeechairWilkes, Garth L.en
dc.contributor.committeecochairRiffle, Judy S.en
dc.contributor.committeememberWard, Thomas C.en
dc.contributor.committeememberDillard, John G.en
dc.contributor.committeememberDavis, Richey M.en
dc.contributor.departmentChemistryen
dc.date.accessioned2014-03-14T21:16:55Zen
dc.date.adate1999-08-04en
dc.date.available2014-03-14T21:16:55Zen
dc.date.issued1999-07-19en
dc.date.rdate2000-08-04en
dc.date.sdate1999-08-02en
dc.description.abstractInorganic-organic hybrid materials have been developed using sol-gel reactions of a trialkoxysilylated organic compound and a metal or semi-metal alkoxide and applied as coatings on polymeric or metallic substrates. Many of these coatings have demonstrated good to excellent abrasion resistance. Abrasion resistant coatings were prepared by hydrolysis and condensation of mixtures of a triethoxysilylated diethylenetriamine (f-DETA), tetramethoxysilane (TMOS), water and an alcohol in the presence of an acid catalyst (a one-step hydrolysis approach). The influences of many formulation and processing variables on the gelation time, optical properties, hardness and abrasion resistance were investigated. An aminolysis mechanism was also proposed to explain the adhesion between sol-gel derived coatings and polycarbonate substrates promoted by a 3-aminopropyltriethoxysilane (3-APS) primer. FT-IR, GPC, 1H and 13C NMR, XPS experiments were conducted to support this mechanism. The f-DETA/TMOS system is essentially a binary system of an alkyltriethoxysilane (T) and a tetraalkoxysilane (Q). At pH 0-2 and pH 4-5, the relative condensation reactivities of the T and Q species in this system were compared using 29Si NMR spectroscopy. After thermal curing, 13C or 29Si solid state NMR spectroscopy was used to estimate the extent of hydrolysis of the urea linkages in f-DETA, the concentration of residual alkoxysilane groups, and the extent of condensation for both T and Q species. The dependence of the morphology of f-DETA/TMOS gels on the pH and the water concentration was also investigated using AFM, SEM and SAXS. Many other trialkoxysilylated organic compounds containing urea, urethane, epoxy and siloxane linkages were also synthesized and utilized to prepare abrasion resistant coatings via a one-step hydrolysis approach, a two-step hydrolysis approach or a moisture-curing approach. Coatings derived from many of these systems or approaches demonstrated abrasion resistance comparable to that of the f-DETA/TMOS coating. Thin coatings were also derived from cubic octasilicate monomers via hydrosilylation or sol-gel reactions. These coatings were very transparent but unfortunately lacked abrasion resistance.en
dc.description.degreePh. D.en
dc.identifier.otheretd-080299-155954en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-080299-155954/en
dc.identifier.urihttp://hdl.handle.net/10919/39013en
dc.publisherVirginia Techen
dc.relation.haspartDisser99.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectAbrasion Resistant Coatingsen
dc.subjectInorganic-Organic Hybrid Materialsen
dc.subjectOptical Plasticsen
dc.subjectSol-Gel Processesen
dc.titleInorganic-Organic Sol-Gel Derived Hybrid Materials as Abrasion Resistant Coatingsen
dc.typeDissertationen
thesis.degree.disciplineChemistryen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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