Sciencemadness Discussion Board

Carbon Foam Refractory Made From Bread

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aga - 18-2-2018 at 14:13

If you make your own bread you can add or remove whatever you like.

Best to keep the yeast, flour and water.

I had a hunch that Sulphur would be good, so tried it.

Tuned out to be less than good.

Unlikely anyone will find an unsliced 10% sulphur bread in any shop.

DrP - 20-2-2018 at 03:42

Quote: Originally posted by aga  
I had a hunch that Sulphur would be good, so tried it.


Is that because it vulcanises rubber?

If you or anyone else wants to try some APP then PM me your address and I'll send some with a SDS. It is pretty safe and inert. As I said - APP is the industry standard charring aid for carbon based polymers.

I don't have the time or facility to bake bread. Maybe soaking it in an APP solution would help, but I think the phase II material would be better from experience. The Phase I soluble stuff is good at stopping flaming, but the Phase II stuff (higher molecular weight) is much better for crosslinking in chars. Maybe mixing into the dough before baking would give the most homogenous distribution of it.

DrP - 20-2-2018 at 04:01

Quote: Originally posted by Chemetix  
I don't have the time to go and try this so don't crucify me. But has anyone tried, or would like to try, dipping their bread refractory foam in a thin mix of plaster and see what happens. Or sodium silicate perhaps, just something to shield the carbon from getting oxidised.


Why would anyone crucify you? Surely all wisdom is welcome, no? Only a total twat would shun your experience and knowledge that you are generously sharing for free here - especially as this is a discussion forum. (have you ever seen a child with play bricks trying to build a wall in multiple columns of bricks rather than overlapping them?.. some kids would welcome being told that overlapping gives a stronger wall.... some just get grumpy and bratty and throw the bricks at you and tell you to do it yourself, lol, I guess it depends on upbringing or something)

I think they tried enclosing the bread off from O2... I do have Nitrogen and would like to try what they have done over nitrogen or some other inert gas but wont get time either. Maybe I could slip something into the furnace at work while other test are going, lol, but I don't want to mess about here really.

I still think APP is the thing to try. A little blowing agent might make the bread rise more also into a larger more porous foam.


[Edited on 20-2-2018 by DrP]

RawWork - 20-2-2018 at 04:04

Expecting porous stuff like bread to have good electrical conductivity does not make sense. The more porous something is, the less conductive it is. Especially carbon which even solid is weak conductor. The only useful stuff i see here is thermal insolator. But only if it's easier to make then any other thermal insolator. I mean the purpose of bread is to be porous, so we already know what properties to expect. Using it as crucible sounds impossible. Try holding water in sponge :P

Fulmen - 20-2-2018 at 04:27

Forgive me if it's been covered, but I couldn't find anything about it. Has anyone tested it's resistance to oxidation at prolonged heat? I'm considering building a furnace, and if it can withstand prolonged heat without a complete absence of air it could be an interesting choice. It wouldn't be directly exposed to the heat of course, I'm imagining it covered with fire clay or high-temp cement.

DrP - 20-2-2018 at 04:29

Quote: Originally posted by RawWork  
Expecting porous stuff like bread to have good electrical conductivity does not make sense.:P


Being fair - they started measuring conductivity and commenting on it as a side discussion due to their observations. The thread is about making a refractory foam. The more porous the foam the better thermal insulation it should have.

RawWork - 20-2-2018 at 05:39

I noticed few posts about best possible electrode in world... Also gases are better insolator.

DrP - 20-2-2018 at 05:42

Quote: Originally posted by RawWork  
Also gases are better insolator.


Thermally too - thus the desire for increased porosity in the foam.

happyfooddance - 20-2-2018 at 08:14

This might be worth mentioning:

Panko (japanese bread crumbs) are made by cooking bread with an electric current rather than in an oven. The bread is consistent from end to end, and makes crumbs whose grains are uniform, unlike a normal loaf, which has variable consistency.

aga - 20-2-2018 at 09:04

Now that is worth mentioning !

Cheers. Will look at how Panko is done

Edit:

A bit of research says that Japanese soldiers in WWII invented a method to make bread using electric current. Most likely a car battery. Will give that a try.

The gluten probably gets elongated more due to the 3x 'rising' cycles. We'll see.

Bought a new Pyrolysis Rig today for 20 euros :

newrig.jpg - 38kB

[Edited on 20-2-2018 by aga]

SWIM - 20-2-2018 at 10:27

Quote: Originally posted by Chemetix  
I don't have the time to go and try this so don't crucify me. But has anyone tried, or would like to try, dipping their bread refractory foam in a thin mix of plaster and see what happens. Or sodium silicate perhaps, just something to shield the carbon from getting oxidised.


GET THE NAILS!!

Seriously, I'd wondered about firing it in molten potassium carbonate for similar reasons.

Might just come apart in the boiling liquid if not tough enough, but if it ever gets cold around here again I've got crude carbonate that needs firing anyway and will give it a go. (assuming I can make bread sink in molten potassium carbonate, might need a 'cement overcoat', or at least some ballast.)

However I am surprised nobody has introduced Marmite into the equation. Not that I expect it would do any good, but it's probably a better use for the stuff than actually eating it.

aga - 20-2-2018 at 11:07

Thinking about it a bit more, Chemetix's idea allows other possibilities.

If the bread is encased in a plaster 'skin' with a hole at one end, then the breakdown products will have to pass through the rest of the material as it pyrolyses, possibly reacting as it does so.

Adding a blob of something (at the opposite end to where the gas-escape hole will be) before dipping it all in plaster would cause it's vapours to also pass through the hot material in this process.

Hmm. Sounding promising.

aga - 20-2-2018 at 11:29

Quote: Originally posted by Fulmen  
Forgive me if it's been covered, but I couldn't find anything about it. Has anyone tested it's resistance to oxidation at prolonged heat?

If you call 2 minutes 'prolonged' then yes, just now, due to your question.

This slice of rye bread didn't come out too well with the new pyrolyser - it isn't conductive.

Here it is raw, subjected to 2 minutes under a 70% Butane/30% Propane flame, then the other side was subjected to 2 mins under a MAPP gas flame.

fresh.jpg - 29kB
buburn.jpg - 34kB
buresult.jpg - 32kB
mappburn.jpg - 35kB
mappresult.jpg - 33kB

This particular sample was a bit iffy to begin with, yet shows how durable it is under heat, even in air.

After this test the toast fell apart when it was picked up. Big chunks, but definitely in bits.

Fulmen - 20-2-2018 at 14:28

Not exactly what I was thinking of, but thank you very much for the experiment. I'm guessing it's heat resistance depends on the charring temperature, guess I'll have to do some experiments once my grill emerges from the snow. Can't use the furnace as it would stink up the basement too much, but perhaps it would be OK after the initial charring?

aga - 20-2-2018 at 14:44

Pyrolysing it well, i.e. to completion seems to be the key.

If the bread is not reduced to 100% carbon it will burn normally.

That sample in the photos i would guess was 90% 'done' before it met the flames.
(new fire thing isn't quite as good as a wood fire)

Some parts did burn with a flame, briefly, during the butane/propane burn.

Edit:

If this MAPP gas works as advertised, the flame temperature is over 2,900 C.

The half-baked pyrolysed bread at least held it's shape, which is amazing.

[Edited on 20-2-2018 by aga]

Fulmen - 20-2-2018 at 23:37

MAPP/air has an adiabatic flame temperature of 2000°C, in reality it will be far lower.

I suspect this is comparable to cooking charcoal. There carbon content ranges from around 50% at 300°C to more than 90% at 1000°C.

aga - 4-3-2018 at 09:38

For anyone interested in using this bread/carbon stuff structurally, the average shrinkage during pyrolisation came out at 27% today.

3 chunks of home made bread were measured, pyrollised in a charcoal fire, then re-measured.

Again the resistance is quite low this time measuring 11.7 ohms in a point-to-point test.

before.jpg - 40kB
after.jpg - 34kB
resist.jpg - 36kB

Here's the supporting data for the shrinkage figure.
Attachment: data.ods (13kB)
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violet sin - 10-4-2018 at 20:38

Latest attempt
- the bake my own bread option went out the window with roof repairs and family time. But bbq dinner offered a shoot from the hip opportunity. These are seed pods from a tree in my yard, a sweet gum.

Pre incineration,
IMAG5349.jpg - 405kB IMAG5351.jpg - 856kB

Post roast
IMAG5352.jpg - 796kB IMAG5353.jpg - 822kB
IMAG5354.jpg - 1.1MB IMAG5355.jpg - 1.1MB

I have a feeling that there may be more loss on further torment. The aluminum foil was as shiny as ever, and the cans label was faint though legible. But they are crispy/brittle. My plan to invest as little time as possible succeeded, family didn't miss me for long. Just closed the bbq vent 95% and walked away.

Every experiment leads to a wealth of ideas for next time on this one for me. Gratifying, cheap, full of room for insane detail if the free time arises.

Drive to work offers thinking time. Takeaway this morning : seed pods can retain geometry... Things like dry cereal such as Kix or cocopuffs could be great preforms... Rice crispy treats are moldable... Rice itself is fairly consistent... We can have compact or foamy preforms to use as ingredients.
,
So adulterated rice crispy treats and a crap-ton of sample compositions will eventually have to be tested.

aga - 11-4-2018 at 00:03

Cool !

They look really interesting. Also looks like they didn't shrink much.

violet sin - 16-4-2018 at 03:54

Tried a second firing on the sweet gum balls, not measured first time. One trial of two balls lost 5.26% more on second firing. Not a tremendous amount and the shape/size distortion was minimal. Though I did not get a caliper on them during any of this.

IMAG5392.jpg - 836kB ^ v IMAG5391.jpg - 980kB

Some lightly frosted puff like cereal. Turns out the coating makes a decent binder after ignition. They lost ~44%

Grapenuts cereal lost ~24% after two trips through the BBQ. First time they were only a deep burgundy / brown. Now a good black.

IMAG5390.jpg - 1015kB ^ v IMAG5407.jpg - 1MB

A little disappointing was a test on tapioca pearls... It did not cook evenly, the one side was exactly like a muffin pouring out. But the interior of that area was well detailed and airy. The pearls did not simply char with my limited heat control. It lost ~21.4%

Then there was a wild shot in the dark mix of wheat gluten, potato starch, Styrofoam balls and a wildly impulsive dab of numerous additives that will give little clue to their individual effectiveness... Below 1-3 , white lithium grease spray and graphite powder worked as a release.

IMAG5385.jpg - 1.1MB IMAG5388.jpg - 1.1MB
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Last from above ^ this idea was Last on and did not receive enough heat to be blackened the whole way, but tomorrow is another day. It's a stainless steam tray insert with a stainless cup set inside, the interspace filled with cereal. I foiled over the top and flip it foil side down on the grill. If all goes well, I'll have a nice foamy crucible shape. I mixed a little confectioners sugar and wheat gluten in as these were not frosted. My son was horrified when I showed him what used to be ~25g of his puffs... Had to be reassured I wasn't going to ruin them all.

We're that to succeed one could try a second coating or brush on paste for a more closed pore look. My better half got me a couple jumbo size boxes of puff cereal... Keeps me out of her kitchen, lol. Plenty of material to play with for a while now.

None of this has been really high heat and no resistance tests were performed. Just weight pre/post BBQ roasting.

aga - 16-4-2018 at 10:39

Superb experimentation violet sin !

You're in lead regarding the number of different items shoved in a fire, also actual Data regarding weight change.

Definitely need the resistance measuring - you might have discovered something awesome already ;)

violet sin - 17-4-2018 at 17:04

Ok so the preform did not work... It easily could work, but this time was no. The whole top portion was stuck in one chunk (nicely), further down was not so. The gluten/sugar mix was not evenly spread despite misting the cereal and folding the powder in. When the cup came out, part of the lower char came dislodged and fell in the recess.

Frosted cereal would be far more convenient or just some kind of rice crispy treat like mixture. The forms are nice and so far seem well suited to my goal.

IMAG5469.jpg - 1.1MB IMAG5470.jpg - 1.2MB IMAG5471.jpg - 1.3MB

So after all this playing around with carbon char foam, and a wide field of possibilities, I narrowed down to one goal. At least first off. I want to play with high temp fun, I don't want to buy ceramic fiber blanket for the prices I've seen... So refactory foamy insulation it is. For a quick and dirty project to test these materials, I wanted to do something like a heating mantle-ish set up.

I know it's more professional to come to the table with a finished product before revealing your plans.. but I literally don't care if I fail here, in fact I'm sure I will, many times at the very least. Lol.

Basic plan is to cast a rough shape as seen above. True up the sides, trim and shape the thing. Then either paint it or wrap and refire it and then paint it with ceramic or plaster etc. Install a through way for wires and standoffs for the element.

I could easily see a small mantle for my 14/20 set taking shape with enough effort. But really the possibilities are immense. Electrodes, catalyst support, insulation... It's wide open. Best to pick one and optimise.

aga - 18-4-2018 at 08:04

Looking good there violet

violet sin - 22-4-2018 at 14:17

Newest test run, same steamer insert form and ss cup center form.

IMAG5518.jpg - 1.3MB IMAG5521.jpg - 1.3MB
-(Pic 1): New kind of frosted puff cereal cap and rice crispy (w/ starch/sugar binder) side shot
-(Pic 2): consequence of over fill was cooking on side = separation rift largely empty.

IMAG5527.jpg - 1.3MB IMAG5533.jpg - 1.4MB
-(Pic 3): Side shot of strata. Was surprisingly TENACIOUS grip on the center form cup,
-(Pic 4): frosted chunks, sans adulterants, really hold shape with minimal contact.

IMAG5540.jpg - 866kB IMAG5507.jpg - 882kB
-(Pic 5): rice crispy preform from center cup, shrunk a lot, but I did add a fair amount of water to make moldable consistency.
-(Pic 6): removed chunk of last experiment.

That of course was not the sum total of objects toasted, but last time it dumped the typed words and loaded pics, assuming too much. A couple things need be further toasted.

There was a flat one with paper towel and sugar with cotton face wipes = deformed easily and cracked.

There was a ovoid shape, 2 small stainless bowls stacked face to face. But the al foil/ss bowls/al foil was a pretty effective heat shield on top of being a good form. It awaits further charting.

Bought more of the overly frosted puffs, I will be toasting them as is later today as well as trying some surface cover mixtures on the previously toasted and failed chunks. Need an atmosphere resistant cover for actual future use to move forward.

This chosen cereal may be a cheap as-is usable material here. It's almost a bit glassy when done, 48% sugar content lol. 2.49$ for a huge bag. This time Will be parchment paper-- aluminum foil-- parchment paper-- char material. I'm just gonna make a block form sans SS pan. I feel that it greatly adds to the cook time. First light was 1:30am, final check was at 5am with more charcoal added @ 3:15am while turning. HOURS in the bbq and yet not complete carbonization. Darn it.


Choice of parchment paper as effective release b/c of excruciating effort to place pieces that didn't char in that place was caused by pinhole in al foil leading it to stick to as bowl. Poor adhesion from poor charing plus sticking = F*$# me running.

No weights were taken b/c family time conflicting with hobby & family > play time :) hopefully mor pics and progress this evening.

mayko - 25-2-2020 at 19:14

Quote: Originally posted by mayko  

Someone brought some nasty BlunderBread hamburger buns to my 4th of July cookout and they've been sitting in the fridge since. Finally, a use for them!



These sat in my freezer until last week. They were dehydrated when I pulled them out. I wrapped each of four in Al foil and stacked them in a steel can, which was then half-buried in a charcoal fire.

Once cool and unwrapped, I found tough, surprisingly strong carbon foam slices. They were much lighter, from ~60% to ~25% of the starting mass of ~34.4g. The bottommost foam was not only the lightest, but the only one for which I could find a detectable (ie, finite) resistance.
Code:
mass (g) resistance (Ohm/cm) Top 20.41 - 13.59 - 10.36 - Bottom 8.22 35k


I can think of at least two possible explanations: heat gradient (hotter at the bottom) and redox gradient (more O2 at the top)

mayko - 26-7-2020 at 09:56

I did a few exploratory experiments with these carbon foams and a sodium silicate solution (waterglass). I tried three basic treatments:

* repeatedly soaking in waterglass, then dilute sulfuric acid, then rinsing

(Na2O)x·(SiO2)y + xH2SO4 -> xH2O + ySiO2 + xNa2SO4


the idea was to coat or permeate the foam with silica. The foam was baked to dry after each dunking in the waterglass, which led to the formation of many tiny sodium silicate bubbles. These structures survive the acid treatment as this photomicrograph show. At high magnification, there appear to be small silicate needles on the carbon.

roastedSilicateWide.jpg - 1.3MB roastedSilicateBub.jpg - 959kB

It seemed to stand up to a MAPP gas torch pretty well; afterwards, the pores of the carbon foam seemed to have been filled with a bubbly/crystalline silicate

blazedSilicate.jpg - 1MB

* soaking in boric acid, baking to dehydrate to boric trioxide, then soaking in waterglass

(Na2O)x·(SiO2)y + zB2O3 -> (Na2O)x·(SiO2)y·zB2O3


Boric acid was dissolved in absolute EtOH, and the carbon foam soaked in the solution. It was dried, then baked to dehydrate, then soaked again. After a couple of repetitions, this was dunked in waterglass and baked dry again. The result was a fluffy, flakey white crust on the foam. When hit with the MAPP gas, the whole structure crumpled, suggesting that the boric/silicate soak had permeated and disrupted the carbon network, such that it lost all integrity when the intersitial material melted. When examined, the silicate/boric material had melted into droplets clinging to the foam surface, which cooled into tiny beads containing air bubbles. I wonder what role the foam geometry (voids, ridges) have in forming the beads?

glassDroplets.jpg - 1MB

* soaking in copper acetate, then soaking in waterglass, then dilute sulfuric

The idea here was to coat the foam with a mixed copper/silicate layer, like you'd see in a chemical garden. After soaking in an ethanol/copper acetate solution and drying, a chunk of foam was cut open. The salt appeared to be mostly but not entirely superficial, with a small amount appearing to have made its way into the interior. When hit with a torch, a thin layer of copper was left firmly adhering to the surface.

After soaking in waterglass, drying, and then sealing with dilute acid, the surface had a light green, foamy appearance. When this was torched, it seems to withstand a lot of heat; afterwards there is a glassy red-brown residue on the surface. Under the microscope it looks to be a mix of copper metal and silicate. It also looks like the silicate is wetting the carbon surface much better in this case than the others.

I wonder to what extent the cupric ion is being reduced by the acetate ion vs. by the carbon substrate...

redFoam.jpg - 981kB wetRedGlass.jpg - 1.3MB

mayko - 23-3-2022 at 08:10

Stein, B. E., Auciello, O., Arellano-Jimenez, M. J., & Perez, B. R. (2022). Fungal Mycelium Conversion into Ultrananocrystalline Diamond via Microwave Plasma Pyrolysis. ACS Sustainable Chemistry & Engineering, 10(10), 3211–3218. https://doi.org/10.1021/acssuschemeng.1c07253

Quote:

ABSTRACT: Fungal mycelium has been touted as an environ- mentally sustainable potential replacement for a wide range of materials commonly used today, including textiles, building materials, and medical bandages. Additional applications of mycelium are possible through pyrolysis, wherein chitin in the mycelium is carbonized to produce useful carbon allotropes like biochar or activated carbon. Here, we demonstrate that this pyrolysis process can be achieved quickly and efficiently with a plasma reactor built around a commonly available kitchen microwave oven. It is found here that this microwave plasma pyrolysis (MPP) process converts the mycelium into a “myco- diamond” matrix containing ultrananocrystalline diamond (UNCD) nanostructures with macro-, micro-, and nanoscale features. Verification of the MPP-induced transformation of mycelium into UNCD is confirmed via complementary material analysis techniques including Raman spectroscopy, high-resolution transmission electron microscopy, and X-ray diffraction. Analysis of the myco-diamond surface morphology was performed via scanning electron microscopy. The MPP process represents a scalable and low-cost method of producing UNCD nanomaterials derived from renewable biological sources.


Attachment: Fungal Mycelium Conversion into Ultrananocrystalline Diamond via Microwave Plasma Pyrolysis-compressed.pdf (1.8MB)
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