Title page for ETD etd-03122003-090131


Type of Document Master's Thesis
Author Jennings, Jessica D.
URN etd-03122003-090131
Title Investigating the Surface Energy and Bond Performance of Compression Densified Wood
Degree Master of Science
Department Wood Science and Forest Products
Advisory Committee
Advisor Name Title
Zink-Sharp, Audrey G. Committee Chair
Frazier, Charles E. Committee Member
Kamke, Frederick A. Committee Member
Keywords
  • bond durability
  • fracture mechanics
  • surface energy
  • densified wood
Date of Defense 2003-02-25
Availability unrestricted
Abstract
Investigating the Surface Energy and Bond Performance of Compression Densified Wood

Jessica D. Jennings

(ABSTRACT)

The bond performance and surface energy of hygro-thermal compression densified wood were studied using comparisons to hygro-thermally treated and control yellow-poplar (Liriodendron tulipifera).

Bond performance was studied using opening mode double cantilever beam fracture testing and cyclic boiling of one half of all fracture samples. Phenol formaldehyde film (PF-film) and polymeric diphenylmethane diisocyanate (pMDI) were the two different adhesives used to bond fracture samples. Hygro-thermal samples bonded with PF-film had significantly higher fracture toughness than control samples, while no difference was found for densified samples. Densified samples bonded with pMDI had significantly higher fracture toughness than control samples while no change was seen for hygro-thermal samples. Boil cycling reduced fracture toughness of hygro-thermal fracture samples only, irrespective of adhesive type.

Surface energy was studied using sessile drop contact angle measurement and the Chang model of acid-base, surface energy component calculation. Water, glycerol, formamide, ethylene glycol, and -Bromonapthalene were used as probe liquids. Densified and hygro-thermally treated yellow-poplar had significantly higher contact angles than control samples. The contact angle trends for densified and hygro-thermally treated wood were found to be the same. Total surface energy as well as the polar and acid components of surface energy decreased with hygro-thermal treatment. The dispersive and base components of surface energy increased with hygro-thermal treatment.

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