Cure of aqueous phenol-formaldehyde resin at elevated water vapor pressures

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dc.contributor.authorBallerini, Aldo A.en
dc.contributor.committeechairKamke, Frederick A.en
dc.contributor.committeememberFrazier, Andrew E.en
dc.contributor.committeememberGlasser, Wolfgang G.en
dc.contributor.committeememberYoungs, Robert L.en
dc.contributor.committeememberWightman, James P.en
dc.contributor.departmentWood Science and Forest Productsen
dc.date.accessioned2014-03-14T21:21:51Zen
dc.date.adate2005-10-20en
dc.date.available2014-03-14T21:21:51Zen
dc.date.issued1994-11-19en
dc.date.rdate2005-10-20en
dc.date.sdate2005-10-20en
dc.description.abstractThe intent of this research was to enhance our knowledge of aqueous phenolformaldehyde resin cure as it is affected by the elevated water vapor pressures that occur during hot-pressing of a wood-based composite. Microdielectric spectroscopy (DEA) was used to monitor the cure reaction, and thermomechanical analysis (TMA), swelling tests and scanning electron microscopy (SEM) techniques were used to characterize the final resin-network. Microdielectric results showed that as the water vapor pressure of the sy stem increases the time to gelation increases. It was also found that the injection of saturated water vapor sharply decreased the gelation time when compared to the other water vapor environmental conditions. In addition, it was found that the higher the water vapor pressure the lower the residual ion viscosity. Thermomechanical analysis and swelling test experiments showed that as the water vapor pressure increases the glass transition temperature and the cross-link density of the cured resin-network decreases. Considerable differences in the morphology of the network were found using SEM. Thus, it can be established that during the curing process under elevated water vapor pressures of a liquid phenol-formaldehyde adhesive some water is trapped into the resin network and it is acting as a plasticizer. A theoretical approach to model the cure kinetics of phenol-formaldehyde has been developed. The model is based on the occurrence of two simultaneous processes (condensation polymerization and evaporation of water) and on the concentration dependency of the activation energy of polymerization.en
dc.description.degreePh. D.en
dc.format.extentxii, 141 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-10202005-102837en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10202005-102837/en
dc.identifier.urihttp://hdl.handle.net/10919/40045en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V856_1994.B356.pdfen
dc.relation.isformatofOCLC# 32749778en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1994.B356en
dc.subject.lcshPhenolic resins -- Curingen
dc.titleCure of aqueous phenol-formaldehyde resin at elevated water vapor pressuresen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineWood Science and Forest Productsen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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