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UBC Theses and Dissertations
Relating pressure response profile during hot pressing to property development in flakeboard Feng, Yan
Abstract
The pressure response profile of a flakeboard during hot pressing was exclusively studied using variables of flake species (aspen and lodgepole pine), flake types (small-size flakes and large-size flakes), resin contents (0 and 8 percent), moisture contents (2 and 6 percent), and press closing times (30, 60 and 90 seconds). This pressure response profile was found to reflect the panel's overall rheological behaviour in relation to each of the variables. Pressure response was related to the development of the panel properties such as vertical density gradient, modulus of rupture, modulus of elasticity, internal bond and dimensional stability, as well as the development of in situ adhesive cure. The development of a panel vertical density gradient was found to depend on the panel overall rheological behaviour during hot pressing and could be well determined either by mat pressure response or by mat displacement response. The development of the panel modulus of rupture, modulus of elasticity, and internal bond, on the other hand, depended not only on the development of the vertical density gradient, but the adhesive cure as well. The in situ adhesive cure could be determined by mat displacement response for a panel with limited rheological response during hot pressing. With large rheological response, the mat displacement was not sensitive to adhesive cure. By monitoring system temperature, mat pressure and displacement response, the developments of panel properties and in situ adhesive cure could be satisfactorily explained. The feasibility of altering panel properties by pressure manipulation was also studied. The introduction of a pressure breathing stage during hot pressing was found to improve properties only in panels with 2 percent moisture content. With 6 percent moisture content, panel properties were adversely affected.
Item Metadata
Title |
Relating pressure response profile during hot pressing to property development in flakeboard
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1994
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Description |
The pressure response profile of a flakeboard during hot pressing was exclusively
studied using variables of flake species (aspen and lodgepole pine), flake types (small-size
flakes and large-size flakes), resin contents (0 and 8 percent), moisture contents (2 and 6
percent), and press closing times (30, 60 and 90 seconds). This pressure response profile
was found to reflect the panel's overall rheological behaviour in relation to each of the
variables. Pressure response was related to the development of the panel properties such
as vertical density gradient, modulus of rupture, modulus of elasticity, internal bond and
dimensional stability, as well as the development of in situ adhesive cure. The
development of a panel vertical density gradient was found to depend on the panel overall
rheological behaviour during hot pressing and could be well determined either by mat
pressure response or by mat displacement response. The development of the panel
modulus of rupture, modulus of elasticity, and internal bond, on the other hand, depended
not only on the development of the vertical density gradient, but the adhesive cure as
well. The in situ adhesive cure could be determined by mat displacement response for a
panel with limited rheological response during hot pressing. With large rheological
response, the mat displacement was not sensitive to adhesive cure. By monitoring system
temperature, mat pressure and displacement response, the developments of panel
properties and in situ adhesive cure could be satisfactorily explained.
The feasibility of altering panel properties by pressure manipulation was also
studied. The introduction of a pressure breathing stage during hot pressing was found to
improve properties only in panels with 2 percent moisture content. With 6 percent
moisture content, panel properties were adversely affected.
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Extent |
4361478 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-02-25
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0075242
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1994-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.