The Forestry Forum

General Forestry => General Board => Topic started by: mooleycow on December 25, 2011, 05:55:47 PM

Title: lignan?
Post by: mooleycow on December 25, 2011, 05:55:47 PM
what do you know about lignan?  extracted from wood.  suppose to be stronger than steel. 
Title: Re: lignan?
Post by: SwampDonkey on December 25, 2011, 06:38:34 PM
It is present in the fine cavities within the mature cell wall where it acts as a bulking agent and reduces the dimensional changes in the cell wall with moisture changes because of it's low hygroscopicity. It gives rigidity and stiffness to the cell wall. It is thermoplastic and used in particle board. Requires specific enzymes of decay organisms to break down lignan, thus rot wood. Wood below the fibre saturation point (MC 26-30%) will resist decay.

[Source: Textbook of Wood Technology, 4th Ed., 1980]
Title: Re: lignan?
Post by: WDH on December 25, 2011, 07:22:18 PM
It is the glue matrix that holds the cellulose chains in the cell walls of the wood cells together.  In the pulp mills, it is dissolved in a strong solution of sodium hydroxide and sodium sulfide (white liquor), turning the solution into black liquor.  This allows the cellulose chains to separate into individual fibers.  The black liquor is concentrated by evaporating out water to give a gear oil type consistency.  Is is blown into a humongous boiler and burned.  The lignin provides the fuel and the heat and lack of oxygen in the boiler melts the sodium into a molten metal and reduces it (strips off all the oxygen atoms to make it highly reactive).  This molten sodium is then added to water and calcium oxide to re-form white liquor to start the process all over again.

So, lignin is the flesh on the bones of the wood cellulose and it is a highly concentrated fuel in the pulping process.  That is more than you probably wanted know, but I used to work in the Power and Recovery Unit in a Pulp Mill  :).
Title: Re: lignan?
Post by: Gary_C on December 25, 2011, 07:32:51 PM
Anyone with a name like mooleycow should be able to educate us about fiber like lignin, cellulose, and hemicellulose. That is what ruminants need to keep their stomachs working well. And being able to digest those woody plant materials is what sets those ruminants apart from other species.  ;D
Title: Re: lignan?
Post by: SwampDonkey on December 25, 2011, 07:40:09 PM
Keeps the man with the shovel busy around the barn to. ;D
Title: Re: lignan?
Post by: POSTON WIDEHEAD on December 25, 2011, 08:06:59 PM
Can SOMEBODY tell ME what WDH and SWAMPDONKEY just said!  smiley_alcoholic_01
Title: Re: lignan?
Post by: SwampDonkey on December 25, 2011, 08:13:52 PM
Basically, it's water resistant. ;D
Title: Re: lignan?
Post by: Texas Ranger on December 25, 2011, 09:29:51 PM
Swampdonkey was talking about mucking out a barn, the rest of it, I don't know.
Title: Re: lignan?
Post by: Coon on December 25, 2011, 10:07:14 PM
All I got out of it was something about the north end of a southbound cow.  :D