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Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
Fax: (608) 231-9592
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New Model for Understanding the Fiber Saturation Point of Wood

Preliminary state diagram of water in wood constructed from literature data on the glass transitions of wood polymers and calorimetric studies on water in wood Samuel Zelinka, U.S. Department of Agriculture Forest Service.
Preliminary state diagram of water in wood constructed from literature data on the glass transitions of wood polymers and calorimetric studies on water in wood Samuel Zelinka, U.S. Department of Agriculture Forest Service.
Snapshot: The fiber saturation point is a key measure of how much water can be held within wood before free water forms in empty spaces within wood structure. Forest Service researchers developed a new model to understand how bound and free water are partitioned within wood. This model can be used to develop more durable wood products.
Summary:

Fiber saturation point (FSP) is an important concept in wood-moisture relations that differentiates between the states of water in wood; the concept has been discussed in the literature for more than 100 years. Despite its importance and extensive study, the exact theoretical definition of FSP and the operational definition (the correct way to measure FSP) are still debated because different methods give a wide range of values. Forest Service researchers developed a theoretical definition of FSP based on solution thermodynamics that treats FSP as a phase boundary. This thermodynamic interpretation allows FSP to be calculated from the chemical potentials of bound and free water as a function of moisture content, assuming they are both known. Treating FSP as a phase boundary naturally lends itself to the construction of a phase diagram of water in wood. The researchers conducted a preliminary phase diagram with previously published data, and the phase diagram was extended to a state diagram by adding data on the glass transition temperatures of the wood components. This thermodynamic interpretation and resulting state diagram represent a potential framework for understanding how wood modification may affect wood-moisture relations.
Princpal Investigator(s):
 Bergman, Richard
 Alanya-Rosenbaum, Sevda


Research Location:
  • Madison, WI


External Partners:
  • University of Wisconsin

Fiscal Year: 2016
Highlight ID: 650
 
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