1. ©USFS

2. Since the first utilization of timber as
a structural material, man has
sought to extend the service life of
wood by reducing moisture
sorption.
• Biblical Times: Pitch
• Ancient Greece: Olive oil
• Roman Times: First use of petroleum treatments

3. Within the last century, petroleum
products have dominated the wood
preservation industry’s moisture
resistant treatments
• John Bethell (1804-1867)
• Full-Cell Process
• Creosote
• Pentachlorophenol

4. In the context of this work, water
repellency is the primary mechanism
for increasing wood durability
European researchers are studying many natural
water-repellent treatments
• Linseed Oil
• Sunflower Oil
• Rapeseed Oil

5. • Enviromental Impact- life of the product
within the environment
• Economic Impact- cost structure of the
product and end-user pricing
The wood-products industry must develop
‘environmentally sensitive’
products to satisfy consumer demand and
the increasing regulatory pressure

6. • Improve the moisture resistance of
southern yellow pine
• Impregnate southern yellow pine (pinus
spp.) with wood pyrolysis oil
• Determine differences between high and
low pressure treatment
• Determine the minimum retention levels
necessary for improved moisture resistance

7. Pyrolysis is a process where cellulosic biomass
is heated in an oxygen-free environment:
•Traditional
•Slow heat transfer, long residence time
•High char and low gas production
•Fast
•Fast heat transfer, short residence time
•Low char and high gas production
•Best suited for pyrolysis oil production

8. (Princeton University)

9. Characteristics:
Contains over 300 compounds
•Two phased:
•Hydrophobic
•Phenolics
•Hydrophilic
•Hydroxyaldehydes
•Hydroxyketones
•Sugars
•Carboxylic Acids

10. Wood pyrolysis oil:
•Rich in hydrophobic phenolic compounds
•Biocidal to wood-degrading fungi.
•Fungi requires moisture:
• Wood is typically impervious to fungal
degradation below 30% MC
•Hydrophobic/biocidal compound:
• economical and environmentally sustainable
treatment option

11. Pyrolysis Specifications:
•Auger-style reactor
•Juvenile pine- forest residue
•Reaction temperatures: 400-540°C
•Homogenized using methanol 50%v/v
•Filtered 5x using #1 Whatman paper
Treatment Specifications:
•Bethell full-cell process
•Dilutions: 50, 40, 30, 20, 10, 5%v/v pyrolysis oil
•1hr. vacuum 1hr. pressure

12. Research Methods: Water Repellency
High Pressure Soak Low-Pressure Soak
Impregnation methods
•High Pressure: 27” Hg Vacuum : 8.5 atm Pressure
•Low Pressure: 27” Hg Vacuum : 1 atm Pressure

13. Drying Vacuum Pressure Evaporation

14. Research Methods: Water Repellency
Materials:
• Whole bio-oil
• Southern Yellow Pine (1” x 1” cubes)
Methods:
1. Conditioned to a stable moisture content
2. Determine specific gravity

21. With increasing pyrolysis oil concentration, the size
of diameter of saturated lumens increased

22. • Pyrolysis oil was successfully impregnated into
Southern Yellow Pine using either high or low
pressure methods
• In a vapor environment moisture resistant
benefits to moisture sorption and tangential
expansion plateaued at concentrations of 10%
• In a soak environment, benefits were directly
related to the concentration of pyrolysis oil
• Leachability of the treatment from the substrate
is the main drawback to this treatment option