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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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Improving Moisture Durability of Forest Products Using Small-angle Neutron Scattering

Forest Products Laboratory (FPL) and Oak Ridge National Laboratory (ORNL) researchers who performed small angle neutron scattering (SANS) experiments to study the effects of chemical modifications and moisture on the wood nanostructure at the ORNL High Flux Isotope Reactor Bio-SANS beamline. From left to right, Joseph Jakes (FPL), Nayomi Plaza (FPL), Shou Qian (ORNL), and Venky Pingali (ORNL). Joseph Jakes, U.S. Department of Agriculture Forest Service.
Forest Products Laboratory (FPL) and Oak Ridge National Laboratory (ORNL) researchers who performed small angle neutron scattering (SANS) experiments to study the effects of chemical modifications and moisture on the wood nanostructure at the ORNL High Flux Isotope Reactor Bio-SANS beamline. From left to right, Joseph Jakes (FPL), Nayomi Plaza (FPL), Shou Qian (ORNL), and Venky Pingali (ORNL). Joseph Jakes, U.S. Department of Agriculture Forest Service.
Snapshot: Moisture is the underlying cause of numerous durability issues in forest products, including decay, lack of dimensional stability, and fastener corrosion. An improved understanding of where and how water is absorbed in wood nanostructure will accelerate researchers' efforts to develop forest products with improved durability. We are developing small-angle neutron scattering into a powerful tool to study water in wood nanostructure.
Summary:

A better understanding of how wood nanostructure swells with moisture is needed to accelerate the development of forest products with enhanced moisture durability. Despite its suitability to study nanostructures, small-angle neutron scattering (SANS) remains an underutilized tool in forest products research. Forest Service scientists investigated nanoscale moisture-induced structural changes in intact and partially cut wood cell walls using SANS and a custom-built relative humidity chamber. Water sorption caused spacing between elementary fibrils to increase with relative humidity, and this swelling accounted for more than half the transverse swelling in S2 secondary wood cell walls. Elementary fibril spacing in longitudinally cut wood cells, which were designed to mimic cells near wood-adhesive bondlines, was greater than the spacing in intact cells above 90 percent relative humidity. This suggested that some cell wall hoop constraint from the S1 and S3 cell wall layers on the S2 layer was released by cutting the cells. Furthermore, increased spacing between elementary fibrils may also create diffusion channels that are hypothesized to be responsible for the onset of fungal decay in wood. The scientists established protocols to use SANS in future research to study adhesives and protection treatments to improve moisture durability in forest products.
Princpal Investigator(s):
 Jakes, Joseph

Fiscal Year: 2016
Highlight ID: 664
 
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