xylitol + quicklime + water = cool putty

Quote: Originally posted by deltaH

EXTREMELY bitter taste - a good thing so animals won't lick it

Hi guys, I've been experimenting with this stuff for quiet a bit now, but destroyed almost every sample I made to explore what it can withstand etc and of course a thousand failures before I got it right, stupidly, I have nothing left but dregs, mostly crystaline powders because I purposefully induced crystallisation to see what not to do, but I promise to buy another packet of xylitol this weekend (still have lots of quicklime left) and make some more and take nice photos. I had some nice 'sculptures' (flat plates and stone shapped things) sitting on my fridge for a week, but then I also managed to destroy these experimenting with them

Sorry for the somewhat long winded explanation about making it, but I wanted to state everything I could think of that I learnt through trial and error so that people have the best results.

One thing I can add though is that the xylitol to quicklime ratio is somewhat flexible, 1:2 on a volume basis for powdered quicklime and granular xylitol works nicely, 1:1.5 also works, but gives quite a hard putty that is somewhat difficult to mould whereas the 1:2 is more plasticine like after kneading hot.

zts16, tasted only a miniscule grain on the tip of my tongue, figured at worst it would consist of calcium xylitol alkoxides, so wasn't too worried about toxcicity of such small amounts. But the extreme bitterness is useful as xylitol is very toxic to dogs and didn't want them eating my putty creations and then dying. Now I am not worried about this, because I think no animal nor human would ever eat this, the bitterness is EXTREME! I also have many ants around and they don't touch it either (does that infer something about the relative intelligence of ants and me )

Paddywhacker I've experiment using sugars, specifically I tried fructose and sucrose. They have a tendency to caramelise sometimes that the sugar alcohols sorbitol and xylitol didn't show (but glycerine does). Sucrose tends to make hard stuff rapidly (more crystalline, less glassy phase), so doesn't work well for a nice plasticine like putty. Sorbitol forms a similar putty, but on standing quickly reverts to powder mass that literally crumbles in ones hand. Xylitol can also undergo this crystal transition in this putty when nucleated, but it is far more stable and looks very stable from first preparation (without reheat). When I make more this weekend, I will save a sample for months and see if it crystallises.

I think during the slaking stage of the CaO, something more than simply slaking takes place in the pressence of the xylitol. I think in the pressence of the very high concentration of sugar alcohol, the CaO slakes but the resulting hydroxide is not crystalline or alkoxides form. I have confirmed that these putties don't form by heating slaked lime powder and the sugar alcohols, for example, there is something special about slaking the CaO in the presence of high concentrations of sugar alcohol that makes this work.

thesmug, by all means you should try it, it's great fun and very pretty and fairly safe. At least no bad smells. When the violent exothermic reaction takes place when the heating runs away, only steam comes off and there is a faint pleasant sweet smell in the air from the xylitol.

If you want a light grey putty in the end, DO try to source a very good quality calcitic burnt lime. I managed to source a sample of fantastic lime eventually, but my initial batches were dark grey because of impurities.

I would love to see people post some little paper weight type sculptures made with this stuff. I'm not very artistic unfortunately

It's tricky working with it though when it's so hot, I used dishwashing rubber gloves, but these are two thin and while one doesn't get seriously burnt with them, it is unpleasant to say the least, especially the kneading stage.

I have heard though that one can buy silicone gloves that are very heat resistant but still give one good hand feel, I'll be looking out for those, failing that, slightly thicker rubber or two pairs may do the trick nicely.

[Edited on 10-4-2014 by deltaH]

Quote: Originally posted by zts16

If you have access to calcium carbonate, you can heat it strongly for a while to drive away CO2 and leave behind CaO.

Photos!

Right then, scaled it down to one third cup measures and now all done. Struggled to get the run away stage started today, i.e. where it mushrooms out and makes lots of steam. Either my quicklime's getting old or I am Simple enough to solve:

microwaved on high for 30-40 seconds while watching it and stopped when I saw it started mushrooming and started mixing with spoon... from there on it goes on it's own steam (excuse the pun).

Anyhow, here are the pics with some descriptions, sorry, I don't have woelen's aptitude for photography

The batch today was pretty poor because I was impatient with the kneading. You might just see that the putty still has small white specks in it, this shouldn't be, though it does give it a nice look

Hope the photo essay helps!



The kind of rubber glove I am wearing are terrible for the kneading stage by the way... they don't insulate one's hands enough and the putty is hot like hell!

[Edited on 10-4-2014 by deltaH]

Thank you all for your comments and compliments!

Since it seemed to me that the putty I made above required further kneading, I decided to try a multiple reheat technique on my previously prepared plate, also to make sure it won't crystallise under repeated reheating (but not overheating!).

The microwave came in very handy again. I heated initially for about 30 seconds on high just to get the plate hot and malleable again from the outside inwards and then started to bunch it up by carefully folding in the outside parts followed by reheating for short bursts. There after, I applied 10-15 second reheats while every time taking it out and using a rolling pin, kneading it and folding it over. The rolling pin proved useful as when it's hot, my thin rubber gloves don't really give me the insulation I would like for hand kneading. This way was far more comfortible!

Anyhow, the point is that the microwave oven is your friend for reheating, but use it sparingly (short intervals of 10-15 seconds) or you may create hot spots that could destroy your putty.

After several repetitions, I got a fairly nicely homogeneous putty, it still had some specks in it, but this seemed to be impurities that there was nothing more I could do about, however, overall, the putty was quiet smooth and resembled, minus the small impurity specks, epoxy resin putty (for example, Pratley Putty if you guys know the brand).

Here is a final photo of a close up. The black and white specks are impurities present in the starting quicklime (it was after all a burnt limestone product). Overall, the putty is a light grey/off white colour, but this depends very much on the starting quicklime you will use.

Blogfast's idea of firing precipitated Ca(OH)₂ is a good one if one has access to the necessary equipment and can reasonably exclude CO₂ during a calcination.

While I have never done this, I would, however, suggest precipitating it from calcium nitrate (a kind of fertiliser) using ammonia solution and then let the slaked lime settle followed by decanting the supernatant water as it's difficult to filter such precipitates.

The residual 'slime' of lime is then simply dried by mild bake before calcining at 500C where the ammonium nitrate impurity will easily decompose to NOx and water during the calcination, so in the end, you should be left with a very pure calcium oxide powder, provided you did it in a kiln and not open so as not to have it exposed to CO₂. If the calcium nitrate fertiliser is too impure, a recrystallization may be in order. One word of warning, NO₂ is very toxic, so baking and calcination are not to be done unextracted indoors!

Either way, if you're not up to this, a bog standard commercial quicklime powder does, nevertheless, work for this application and some may even find the grey colour appealing

Finally, if your quicklime powder is quiet fine or very active, it may be wise to use cold water when preparing the putty to prevent too rapid slaking! You can always microwave the resulting syrup for 30-60 seconds on high or until it starts to mushroom out if you struggle to get the slaking reaction properly going by self heating.



I am trying to name it something, so far the best I could come up with is xyca putty, pronounced zee-ka or z-eye-ka putty (I suspect American users would preffer the former). Could also write it as just zeeka putty in that context.

Please help by suggesting other names or comment on the existing idea for one

My wife just informed me that 'zaika', spelled зайка, means 'bunny' in Russian, as in an affectionate term a man might call a woman, rofl... oops!

Still like the name Zeeka Putty, even if it is my sweet bunny putty rofl!

[Edited on 12-4-2014 by deltaH]

Quote: Originally posted by HeYBrO

Calitol putty?Give credit if you use haha

Quote: Originally posted by blogfast25

Quote: Originally posted by zts16   If you have access to calcium carbonate, you can heat it strongly for a while to drive away CO2 and leave behind CaO. Do you realise what kind of temperatures and heating times are needed to produce significant quantities of quick lime that way? Hint: it really only gets going from about 1000 C. If you're hell bent on making quicklime from limestone, dissolve it in HCl, precipitate as Ca(OH)2 with a base, filter and wash. Ca(OH)2 loses its water from about 500 C. [Edited on 10-4-2014 by blogfast25]

Quote: Originally posted by Eddygp

Later, this solid would harden and wouldn't bounce as much, probably because of some sort of cross-linking cycles.

Crystallization problem in xylitol quicklime putty

Aw shoot... seems that crystallization is setting in to my hardened putty a mere couple of days after reworking it using microwave reheat (see photo). One can see a tumorous mass of white powder material forming and expanding from the edge. There are other smaller masses developing all over the show.

I will now be focusing my efforts on stabilizing the formulation.

My gut feeling tells me using a blend of polyalcohols/sugar alcohols may be a good way to go to depress the temperature of this phase transition.

Since sorbitol and glycerine showed very rapid formation of this white powder stuff upon reacting with quicklime, I would think they're not good candidates to blend with the xylitol. There's the off-chance that chelation by multiples of three hydroxyl groups favours crystalline products with calcium.

Again, I come back to erythritol, but since I have no OTC source for it in South Africa, that leaves me just one other option... glycols, either ethylene or propylene glycol (I'd prefer the latter due to its low toxicity).

So I will be substituting the water addition step in the preparation with the addition of antifreeze solution to my xylitol and quicklime mixture, using a little more than what I would normally have to make up the required water balance.

The fluorescent dye in antifreeze should add a nice colour to my putty

I'll keep thread updated with new findings and pictures as soon as I can!



[Edited on 15-4-2014 by deltaH]

Now before I used unslaked lime to introduce calcium into the system to make the putty harder and slow down crystallisation.

This time I'm going to try an interesting twist.

I have quite a bit of calcium lactate gluconate (CLG) left over from molecular gastronomy experiments. It's a high purity and very soluble form of food grade calcium.



The lactate and gluconate anions seem particularly suitable for dissolving into a polyol glass with its unsymmetrical nature aiding the suppression of crystallisation and plasticization, so I'm going to try to saturate the xylitol-erythritol eutectic with CLG to get a TRANSPARENT product... hopefully.

It will probably be less putty-like since it would lack the calcium hydroxide filler and more glass-like, but I think this would be a cool new twist to investigate.

I'm hoping that a much higher dissolved calcium content in the polyol, combined with the eutectic mix, might make the glass stable w.r.t crystallisation, hopefully indefinitely.

Also, the glass should be edible, though it would give you a runny tummy from the polyols I think the bitterness previously was due to the lime.

Anyway, any thoughts and suggestions welcome.

Attachment: polyol eutectics.pdf (1.8MB)
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The authors of that paper attached investigated the eutectic for heat storage melts and noted in their conclusion that...

Thanks for helping to think of applications EC1 for I can't see many myself besides for it being surprisingly fun stuff to play with for some reason (inner child psychology at work?).

Unfortunately, the lime putty melts when heated so I can't see how it could be put to work in the fashion you suggest.

However, along the lines you are thinking, it might be possible to form it in the shape of something you want while it's a putty, then immerse it in say a saturated sodium carbonate solution overnight so that you dissolve out the polyol and convert the lime to calcium carbonate... and many variations on this theme of using the polyol as a soluble templating binder.

The problem is I tried this once but it doesn't work, the whole thing just dissolves into a soft mush of calcium carbonate. One needs the calcium hydroxide to crystallise in an interlocking fashion for this to work well. Maybe it simply required a higher lime ratio or some other condition specific trick, like doing it slower or something else, I don't know.

If I can make transparent glasses with calcium salts, it might have more applications.

Thanks for the ideas, keep them coming please!

[Edited on 10-10-2015 by deltaH]

I finally got around to messing around a little more with this. Nothing particularly exciting to report.

Xylitol and erythritol eutectic + quicklime in similar proportions as xylitol + quicklime yields a nearly identical material. I have formed a flate plate of the material and will wait to see if crystal blooms develop over the next couple of weeks.

Eutectic + calcium gluconate lactate (CGL) was a flop, yellowing started on strong heating indicative of condendation reactions. Evidently the CGL is too basic for this system. Nothing particularly interesting formed on cooling beside a tacky goop typical of sugar with some crystallisation, presumably the CGL.

I have boric acid, so decided to experiment with borate condensations. 1:1 molar xylitol and boric acid when heated yields much water, presumably either borate esters are formed or the boric acid dehydrates to metaboric acid or both. On cooling, a crystal clear glass results, which was cool, but it's brittle and weak, so not as much fun to play with as my putty.

The putty is still the most interesting to me, particularly because of its relative hardness and strength. I wish I understood what was going on.

I feel somewhat confident that the lime slakes, but that slaking in conc. sugar alcohols results in a very different morphology. I can speculate that perhaps this forms a more amorphous calcium hydroxide-sacharate. When you dissolve the putty in excess water, you suddenly see voluminous amounts of a bright white material form with the consistency of a thick cream (but initially it's viscous but not gel like), but this happens only after addition of a certain amount of water, so I definately think there is some interaction between the polyol molecules and the calcium hydroxide in this putty form, upon excess dilution you get almost a phase change into ordinary slaked lime and dissolved polyol.

Kneading seems important during the cooldown, it improves the slaking and makes the resulting putty very clay-like. I wish I could automate this kneading, it's very hard to do it at the high temperature even when wearing thick gloves. What I need is REALLY thick rubber gloves to be pain-free

Anyway, that's all for now, what I'm keen to see is if this erythritol eutectic employed will stabilise the material against crystallisation blooms that set in after several days. Crossing fingers.

I want to try to make some kind of casting with this stuff if I can and play with colouring it, but for that I need it stable long term first!

I also need a kenwood machine for the kneading of larger quantities. A heated bowl would not go amiss to keep this soft, easily done with a steel bowl

Oh forgot to say that the putty is initially slightly tacky like a sugar, but after 48h its not tacky at all and similar to a matt ceramic. Presumably the surface forms some calcium carbonates that passivates it from being tacky, so if any of you make this and are disappointed with the initial stickiness, just put your piece aside for 48h, it will correct itself.

[Edited on 26-11-2015 by deltaH]