Cellulosic and lignocellulosic structural materials and methods and systems for manufacturing such materials
Methods of treating wood and wood products include irradiating untreated wood having a first molecular weight with ionizing radiation to cause an increase in the molecular weight of a cellulosic component of the wood to a second, relatively higher molecular weight.
1. A method of treating wood, the method comprising:
irradiating wood having a first molecular weight with electron beam radiation while controlling a gas blanketing the wood through which the electron beam passes, electrons of the beam having an energy of about 0.5 to about 5 MeV, to provide treated wood, in the form of sawn lumber or a finished wood product selected from the group consisting of solid wood objects and plywood, in which a cellulosic component of the wood has a second, relatively higher molecular weight at least about 10% higher than the first weight.
2. The method of claim 1 , wherein the gas blanketing the wood comprises a gas selected from the group consisting of nitrogen, oxygen, ozone, nitrogen dioxide, sulfur dioxide, and chlorine.
3. The method of claim 1 , further comprising quenching the irradiated wood.
4. The method of claim 3 , wherein quenching is performed in the presence of a gas selected to react with radicals present in the irradiated wood.
5. The method of claim 1 , wherein the increase in molecular weight is at least 50%.
6. The method of claim 1 wherein irradiating comprises irradiating multiple times.
7. The method of claim 1 wherein the wood has multiple sides and irradiating comprises irradiating more than one side of the wood.
8. The method of claim 1 wherein the wood is irradiated at a dose rate of at least 0.5 Mrad/s.
9. The method of claim 8 wherein the wood is irradiated at a dose rate of at least 1 Mrad/sec.
10. The method of claim 1 wherein the wood product comprises plywood.