dc.contributor.author	Renneckar, Scott Harold	en
dc.contributor.committeecochair	Zink-Sharp, Audrey G.	en
dc.contributor.committeecochair	Glasser, Wolfgang G.	en
dc.contributor.committeemember	Ducker, William A.	en
dc.contributor.committeemember	Frazier, Charles E.	en
dc.contributor.committeemember	Gatenholm, Paul	en
dc.contributor.committeemember	Ifju, Geza	en
dc.contributor.committeemember	Rials, Timothy	en
dc.contributor.department	Wood Science and Forest Products	en
dc.date.accessioned	2011-08-22T19:04:15Z	en
dc.date.adate	2004-08-26	en
dc.date.available	2011-08-22T19:04:15Z	en
dc.date.issued	2004-07-16	en
dc.date.rdate	2004-08-26	en
dc.date.sdate	2004-08-23	en
dc.description.abstract	For the first time, a novel processing method of co-refining wood and polyolefin (PO) by steam-explosion was scientifically explored for wood-thermoplastic composites without a coupling agent. Traditional studies have addressed the improvement of adhesion between components of wood thermoplastic composites through the use of coupling agents such as maleated PO. The objective of this study was to increase adhesion between wood and PO through reactive processing conditions of steam-explosion. PO characteristics, such as type (polyethylene or polypropylene), form (pellet, fiber, or powder) and melt viscosity were studied along with oxygen gas content of the steam-explosion reactor vessel. Modification of co-processed wood fiber was characterized in four studies: microscopy analysis of dispersion of PO with wood fiber, sorption properties of co-processed material, chemical analysis of fractionated components, and morphological investigation of co-processed material. Two additional studies are listed in the appendices that relate to adsorption of amphiphilic polymers to the cellulose fiber surface, which is one hypothesis of fiber surface modification by co-steam-explosion. Microscopy studies revealed that PO melt viscosity was found to influence the degree of dispersion and uniformity of the steam-exploded material. The hygroscopic nature of the co-processed fiber declined as shown by sorption isotherm data. Furthermore, a water vapor kinetics study found that all co-refined material had increased initial diffusion coefficients compared to the control fiber. Chemical changes in fractionated components were PO-type dependent. Lignin extracted from co-processed wood and polyethylene showed PO enrichment determined from an increase of methylene stretching in the Fourier Transform infrared subtraction spectra, while lignin from co-processed wood and polypropylene did not. Additionally, extracted PO showed indirect signs of oxidation as reflected by fluorescence studies. Solid state nuclear magnetic resonance spectroscopy revealed a number of differences in the co-processed materials such as increased cellulose crystallinity, new covalent linkages and an alternative distribution of components on the nanoscale reflected in the T1Ï relaxation parameter. Steam-explosion was shown to modify wood fiber through the addition of "non-reactive" polyolefins without the need for coupling agents. In light of these findings, co-refining by steam-explosion should be viewed as a new reactive processing method for wood thermoplastic composites.	en
dc.description.degree	Ph. D.	en
dc.format.medium	ETD	en
dc.identifier.other	etd-08232004-164234	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-08232004-164234	en
dc.identifier.uri	http://hdl.handle.net/10919/11239	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	Chapter_7_Morphological_Changes.pdf	en
dc.relation.haspart	Dissertation_front.pdf	en
dc.relation.haspart	CHAPTER_6_Chemical_Changes.pdf	en
dc.relation.haspart	Chapter_3_Compositional_Analysis.pdf	en
dc.relation.haspart	Chapter_4_Microscopic_Analysis.pdf	en
dc.relation.haspart	Chapter_5_Sorption_Studies.pdf	en
dc.relation.haspart	Chapter_8_Conclusions.pdf	en
dc.relation.haspart	Appendices.pdf	en
dc.relation.haspart	vitae.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	confocal laser scanning microscopy	en
dc.subject	13C NMR	en
dc.subject	fractionation	en
dc.subject	thermogravimetric analysis	en
dc.subject	biopolymer	en
dc.subject	cellulose	en
dc.title	Modification of Wood Fiber with Thermoplastics by Reactive Steam-Explosion	en
dc.type	Dissertation	en
thesis.degree.discipline	Wood Science and Forest Products	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Ph. D.	en

Modification of Wood Fiber with Thermoplastics by Reactive Steam-Explosion

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