Sciencemadness Discussion Board

Artificial Ivory from Potato?

Sublimatus - 19-12-2012 at 22:06

There are some mentions in old and new publications about a process by which a potato can be turned into an alternative for animal ivory.

The process is vaguely described in Buchanan's Journal of Man, The Scientific Enquirer, and The Machinist's Bedside Reader:
Quote:
Buchanan's Journal of Man, May 1887, Volume 1, Number, Page 24.

ARTIFICIAL IVORY. - We shall no longer need the elephant for ivory. Compounds of a celluloid character, made from cotton waste, can now be made hard as ivory, or flexible or soft as we wish. White and transparent, or brilliantly colored, it can be handled like wood cut and carved, or applied as a varnish. An artificial ivory of creamy whiteness and great hardness is now made from good potatoes washed in diluted sulphuric acid, and then boiled in the same solution until they become solid and dense. They are then washed free of the acid and slowly dried. This ivory can be dyed and turned, and made useful in many ways.

Quote:
The Scientific Enquirer, January 1888, Volume 3, Page 149.

Artificial Ivory. - Much of the so-called ivory now in use is simply potato. A good, sound potato, washed in diluted sulphuric acid, then boiled in the same solution, then slowly dried, is all ready to be turned into buttons and innumerable other things for which ivory was formerly used.

I haven't seen the text in The Machinist's Bedside Reader myself, but I'm told that it doesn't give any more details than the other two excerpts. These are the only references I can find.

Note that the second reference is published only one year after the first and the language is very similar. My guess is the second publication was inspired by the first. Neither appear to be very scientifically rigorous, given the time and subject reported in the rest of the publications.

I tried boiling a potato in 10% (wt/wt) sulfuric acid for a few hours, but as one might expect, the product is just a soft, well-cooked potato.

I plan on trying higher concentrations of sulfuric acid, but I'm curious to know if anyone has any ideas if this is a plausible process, or just plain crap. I can imagine that the sulfuric acid might act to rearrange the starches in the potato to give a more cross-linked and solid material, but biological systems are not my specialty.

12AX7 - 20-12-2012 at 02:36

Hmm, doesn't make sense, at least with regards to starch. Acid breaks down polysaccharides, including cellulose, though usually higher concentrations (25-50% acid) are used for such purposes (or just an enzyme). But this gets you sugar, not plastic. There isn't much else in a potato to play with -- a little protein (depending on variety), and a couple trace vitamins and minerals.

I would think, if you boiled and pureed a potato long enough, you'd gelatinize the whole thing, which on cooling, should form a solid, formless brick, which on slow drying (since the outside will shrink faster than the inside, risking cracks), should leave a nice solid hunk of starch. But this doesn't require acid as far as I know. Maybe it helps with cell lysis or breakdown or something?

Oddly enough, lye finds more use in foodstuffs than sulfuric acid, as far as I can recall. Acids are certainly used, but organic acids, chiefly lactic and acetic, are more than sufficient. Lime or lye is sometimes used to break down proteins, mainly if you wanted to make your own hominy, certain kinds of pickled olives, or the dreaded lutefisk.

Tim

Zephezek - 24-12-2012 at 08:06

Unmm............As far as I know, it makes no sense..............The sulfuric is used to break down the starch in my experiments......Maybe we can get some glucose by boiling the potato in sulfuric

PHILOU Zrealone - 28-12-2012 at 15:51

1°)What are the articles infos?
They speak of a celluloid compound of cotton waste and of potatoes.
They speak of dilluted H2SO4.

2°)What are other facts?
H2SO4 dilluted hydrolyses polyoses into lower MW oses but too concentrated H2SO4 carbonizes oses.
Middle concentration H2SO4 might induce dehydration of polyols what results in alcenic double bonds, in aldehyd and keto groups (after rearrangement with viccinal hydroxy group), in ether linkage formation and in crotonisation.
Hemiacetals and acetals are made from alcohols and aldehyd reacting together with the help of an acid catalyst; water is formed and the reverse reaction is possible unless water is taken away from the media.
When heated in the presence of acids, furfural irreversibly solidifies into a hard thermosetting resin.

3°)What is possible then?
When H2SO4 is sufficiently dilluted, hydrolysis of cotton cellulose and of potatoes starch into lower MW oses like glucose happens.
While boiling the water goes away and the H2SO4 concentrates as does the non volatile oses.
Then dehydration of hexoses happens to form methylol-furfural (and the like molecules).
Then acidic induced polymerisation and crotonisation with entrapped unreacted material...yielding a hard resin.

At that time ivory was of great concern to make snooker balls...scientist where trying to find substitute for it and found that nitrocellulose (cellulose polynitrate ester) was a good candidate after being mixed with a plasticizer (camphor)...wich received the name celluloïd.


[Edited on 29-12-2012 by PHILOU Zrealone]

zed - 26-2-2013 at 12:59

Wonderful stuff, really. Nitrocellulose makes a lovely ivory substitute, that feels like, and looks like the real deal.

Until off course, you expose it to flame. It then ignites easily. And, once ignited, it cannot be extinguished. It burns with the fury of the fires of Hell.

I once gifted my Mom with a beautiful Ivory hand mirror. An errant cigarette came into contact with it. It erupted into flames, burned wildly until all of the nitrocellulose was consumed, and in the process buried itself 1/2 inch deep in a solid wooden floor.



AndersHoveland - 26-2-2013 at 15:48

I would think the concentration of the sulfuric acid would be important. It would have to be concentrated enough to dehydrate and cause further polymerization of the starch, but not concentrated enough to carbonize it. Probably the proper concentration is within the 60 to 90% range.

Obviously if the acid is of lower concentration, it will just catalyze hydrolysis, and further break down the starch.

If I can make a suggestion, adding some glycerine, loose polyvinyl alcohol, ethylene glycol, or possibly even polyethylene glycol to the mix might help harden the celluloid substance.

It might even be possible to combine this substance with other resinous polymers:
http://www.sciencemadness.org/talk/viewthread.php?tid=20311

You could probably even add furfural. Although furfural resin is a dark black red color, which would result in discoloration.

[Edited on 27-2-2013 by AndersHoveland]