NightHawkInLight Posted April 14, 2011 Posted April 14, 2011 I recently attempted to make nitrocellulose with 100% cotton paper (acid free). It burned with a flame that contained a slight bit of green and left a large amount of ash. More or less it simply looked like standard non-nitrated(?) paper burning, only it did so more rapidly. There have got to be chemicals in the cotton that are preventing proper nitration. I used the exact same process to make this flash cotton, which obviously burns very cleanly: http://www.youtube.com/watch?v=Nbt057a8Zzc This is what I have found with a little searching: In the paper making process, acid-free paper is treated with calcium or magnesium bicarbonate. These chemicals neutralize the natural acids in the wood pulp. The chemical mixture is absorbed by the pulp and helps to stop new acid from forming. Once treated, this paper has an alkaline reserve of two percent or greater. The paper materials made with this process will be preserved for at least 100 years. Any ideas on what I could do?
50AE Posted April 14, 2011 Posted April 14, 2011 (edited) Sinking the paper in a dilute solution of weak acid (acetic for example) will result in the acetates of Mg or Ca. Make sure you choose an acid where the resulting salts are soluble. The acetates are. I'm not sure if the acid solution wouldn't weaken the paper though. Edited April 14, 2011 by 50AE
NightHawkInLight Posted April 15, 2011 Author Posted April 15, 2011 Sinking the paper in a dilute solution of weak acid (acetic for example) will result in the acetates of Mg or Ca. Make sure you choose an acid where the resulting salts are soluble. The acetates are. I'm not sure if the acid solution wouldn't weaken the paper though. Very good thought. I'm sure the acid won't hurt the paper. Vinegar should do the trick. I'll give it a shot coming up in the next few days. The NC I made earlier is probably loaded with sulfates which the carbonates left behind in the acid bath. That could be what's slowing the burn and leaving so much ash.
Mumbles Posted April 15, 2011 Posted April 15, 2011 Typically, from what I've read, paper needs longer nitration times that cotton balls or pads typically do. The paper fibers are packed quite densely.
NightHawkInLight Posted April 15, 2011 Author Posted April 15, 2011 Typically, from what I've read, paper needs longer nitration times that cotton balls or pads typically do. The paper fibers are packed quite densely. I gave it a good 45 minutes and some of the paper was very slowly being eaten away I noticed. There were some very thin spots by the time I was done. That was a little odd to me, I've never noticed that before. Much of it seemed fine though. It seems to be good quality cotton, it stayed bleach white when I poured the acids on, whereas usually there's some slight discoloration at first as the cotton is dehydrated. My chemistry is more than likely flawed in that last statement.
WSM Posted April 15, 2011 Posted April 15, 2011 Sinking the paper in a dilute solution of weak acid (acetic for example) will result in the acetates of Mg or Ca. Make sure you choose an acid where the resulting salts are soluble. The acetates are. I'm not sure if the acid solution wouldn't weaken the paper though. Some of the cellulose fibers may be converted to cellulose acetates. Another (weaker) acid might work, try carbonic acid. Regular soda water (from a grocery store) may well wash out the carbonates without damaging the cellulose fibers. I'm not sure about calcium but the magnesium carbonate is soluble in carbonic acid and should be washed out by it. A weak solution of HCl should take care of calcium but I don't know it's effects on cellulose. Have you thought of looking for 100% cotton paper without acid inhibitors? Some things to consider. WSM
WSM Posted April 15, 2011 Posted April 15, 2011 (edited) One other thought occured to me; the "slight amount of green" in the flame. I wonder if they treated the paper with boric acid or sodium borate (borax)? This would need to be removed as well. These two salt may be harder to remove, being much less soluble (~4% is a saturated solution!) . Perhaps wash the paper with methanol and dry first and then the other treatments to remove other acid neutralizers/stabilizers? If the slight green is due to barium salts, pray it isn't the sulfate. Removing that would be a tough job I believe. Still thinking... WSM Edited April 15, 2011 by WSM
NightHawkInLight Posted April 15, 2011 Author Posted April 15, 2011 You know I thought about looking for paper without acid inhibitors, but I just assumed it would be tough to find because it's such an inferior paper for the usual use. Finding one that is not treated yet is still 100% cotton seems unlikely, but I could easily be wrong. Certainly something to look into. At the moment I'm just trying to think of a good way to use the other 99 sheets of paper I already have that cost me $8. I guess I could just use it as paper if I have to. There's a thought. Thanks for the tips. I guess I have a lot of things I can try.
Mumbles Posted April 15, 2011 Posted April 15, 2011 Making cellulose acetate generally requires much harsher conditions than vinegar strength acetic acid. It's an esterification reaction and is still governed by equilibrium. All the water will surely keep it at 100% for all intensive purposes. However, if you were worried, just use dilute nitric acid instead of acetic acid. Any cellulose nitrate formed will just be a head start. I wonder if the slight green is perhaps copper. It's often used as a bleach for paper products, though I'm not sure about high quality acid-free paper. It's used the same as some bleaches which have a small amount of blue dye in them. A slightly blue hue appears whiter to human eyes than a pure white. You seem like the kind of guy who get into making his own paper, so there is always that option. I've done it before, it's not hard, especially if you already have screens for pyro.
NightHawkInLight Posted April 15, 2011 Author Posted April 15, 2011 Maybe the trick is to make NC from cotton balls and then form it into paper after.
WSM Posted April 15, 2011 Posted April 15, 2011 Maybe the trick is to make NC from cotton balls and then form it into paper after. Flash paper is available from special effects houses (I know) and magicians supply houses (I think), so the quality of paper must exist. The problem at hand is locating these sources. If you have a source for laboratory filter paper, NC filter paper is one offering. Perhaps filter paper in bulk would work for nitrating? WSM
NightHawkInLight Posted April 15, 2011 Author Posted April 15, 2011 Flash paper is available from special effects houses (I know) and magicians supply houses (I think), so the quality of paper must exist. The problem at hand is locating these sources. If you have a source for laboratory filter paper, NC filter paper is one offering. Perhaps filter paper in bulk would work for nitrating? WSM This is true. I'll have to do some digging.
NightHawkInLight Posted April 16, 2011 Author Posted April 16, 2011 I can bring you some tomorrow if you'd like. A few sheets would be great!
Bilbobaker Posted April 16, 2011 Posted April 16, 2011 A few sheets would be great!Comparative videos please..
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