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Author

Xiaofei Ye

Document Type

Thesis - University Access Only

Award Date

1999

Degree Name

Master of Science (MS)

Department

Agricultural and Biosystems Engineering

First Advisor

James Julson

Abstract

The goal of the research was to determine comparative properties of dry-formed hardboards (828) and dry-formed medium density fiberboards (MDF) bonded with a conventional urea-formaldehyde resin or a soy-flour-based adhesive (which consisted of 70% soy flour and 30% phenol-formaldehyde). Th e fiber furnishes contained pure wood fiber, pure agrofiber (wheat straw fiber or soybean straw fiber), or 50% wood fiber/SO% agrofiber. The fiberboard properties evaluated were thickness swell (TS), modulus of rupture (MOR), modulus of elasticity (MOE), internal bond strength (IB), and screw holding capacities. The results showed that the soy-flour- based adhesive provided significantly high er mechanical and water resistance properties than urea-formaldehyde resin for hardboards. Medium density fiberboards bonded with the soy-flour-based adhesive had comparable MOE and lower MOR, IB, and screw holding capacities than those bonded with urea-formaldehyde resin. The soy-flour-based adhesive was as good as or better than urea-formaldehyde resin in water resistance for both MDF and S2S. The agrofibers were comparable to or better than wood fiber for MOE but had lower MOR and screw holding capacities. Both agrofibers provided higher IB than wood fiber. Wheat straw fiber produced significantly higher MOE than wood and soy straw fiber. Pure soy straw fiber result ed in higher IB than pure wheat straw fiber. For other properties, soy straw fiber was comparable to wheat straw fiber. The thickness swell of fiberboard increased with increasing percentages of wheat straw fiber and soy straw fiber for both MDF and S2S. Fibers rather than adhesives were the major contributor to thickness swell. The 50% agrofiber composition provided comparable mechanical properties (except IB which was higher for agrofibers) and comparable TS to pure wood fiber for MDF. For S2S, all properties were comparable between 50% agrofiber composition and pure wood fiber.

Library of Congress Subject Headings

Fiberboard -- Testing
Adhesives -- Testing
Soybean products

Format

application/pdf

Publisher

South Dakota State University

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