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dc.contributor.authorSchmidt, Robert G.en_US
dc.date.accessioned2014-03-14T20:21:30Z
dc.date.available2014-03-14T20:21:30Z
dc.date.issued1998-01-28en_US
dc.identifier.otheretd-22798-141819en_US
dc.identifier.urihttp://hdl.handle.net/10919/30352
dc.description.abstractPhenol Formaldehyde (PF) and polymeric isocyanate (pMDI) are the two main types of adhesives used in the production of structural wood-based composites. Much is unknown about various aspects of adhesion between these two types of resins and wood. The present research describes the development of techniques which will permit an enhanced understanding of 1.) the extent of cure of PF within a wood based composite, 2.) the scale of molecular level interactions between PF and pMDI and wood, 3.) mechanical performance and durability of wood-adhesive bonds. Correlations were established between conventional methods of characterization of neat PF (thermomechanical analysis, swelling studies) and measurements made using 13C CP/MAS NMR. These correlations were then utilized to characterize PF cured in the presence of wood. The use of 13C labeled PF allowed estimates of relative degrees of resin conversion to be made. The use of 13C and deuterium labeled PF allowed qualitative estimates of resin molecular rigidity to be made. The scale of molecular level interactions between PF and pMDI and wood was probed using NMR relaxation experiments. Evidence was shown to suggest the formation of an interpenetrating polymer network (IPN) morphology existing at both types of wood-resin interphases. The formation of the IPN morphology was strongly influenced by resin molecular weight, cure temperature and the presence of solvent. A new test geometry for the evaluation of the fracture toughness of wood-adhesive bonds was developed. Consistent and reliable results were obtained. It was found that low molecular weight PF possessed enhanced durability over high molecular weight.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartSCHMIDT.PDFen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectinterpenetrating network formationen_US
dc.subjectIPNen_US
dc.subjectpMDIen_US
dc.subjectisocyanateen_US
dc.subjectphenol formaldehydeen_US
dc.subjectPFen_US
dc.subjectmechanisms of adhesionen_US
dc.titleAspects of Wood Adhesion: Applications of 13C CP/MAS NMR and Fracture Testingen_US
dc.typeDissertationen_US
dc.contributor.departmentWood Science and Forest Productsen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineWood Science and Forest Productsen_US
dc.contributor.committeechairFrazier, Charles E.en_US
dc.contributor.committeememberWightman, James P.en_US
dc.contributor.committeememberKamke, Frederick A.en_US
dc.contributor.committeememberWard, Thomas C.en_US
dc.contributor.committeememberGlasser, Wolfgang G.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-22798-141819/en_US
dc.date.sdate1998-01-28en_US
dc.date.rdate1998-03-31
dc.date.adate1998-03-31en_US


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