Fibre powder

I'm opening this thread to call on anyone that may have worked with fibre powder, be it cellulose, oat husk, coconut, apple etc fibre powder.
What would be a good and cheap supply of this and where could I get it?
I'm looking fos something that has a very fine grain size (50 - 100 micro-meter) so that i can use it as a filler for resins that by itself are very stiff but brittle.

I have found cellulose powder as a nutritional additive on Amazon for 6$ per 250g wich I think is ok for testing purposes, but would be to expensive for the final mix. I'm looking for prices around 6$ a kg or below.

Any ideas?

Have you checked pet or livestock supply places? They might have animal feed grade cellulose and psyllium at lower prices. I'm pretty sure psyllium is used as a supplement for horses, so you should be able to get it in large quantities.

Hi Fernando,

... try icing shugar and starch, as said before - if the resin didn't solve it, then the stuff should do a good job ...

I tried powders from plastic, glass, gold, iron, graphite, zement and sand - and some bigger sized particles like 1-100micron-glass-spheres, plastic-spheres and bigger iron-spheres too ...

Laser-toner-powder (latex and graphite/bucky-balls) tend to harden and form a sort of resin too after some time, so it's a testing, which solvent works best.

For pastes and laser-sintering i used dexpanthenol/water, vaseline, fluid wax, wool-wax (lanolineum), glycerine, some mineralic, synthetic and vegetable oil, gelatine and different fluid soaps ...

My next task is ceramic-powder and some ready-mixed pastes, which i 'optimize' for better dispensing, hardening/drying and laser-sintering.

Another experiment is ink-jetting salt-water on a powder-surface and melting the powder with an IR-heater, so the salt-lines act as separating in the 3D-object ...

Viktor

This fellow uses ordinary wheat flour as epoxy filler.
[www.gsahv.pp.fi]
(Do read it, it's a lovely writeup.)
"Hint:
Instead of commercial epoxy fillers (=expensive) or saw dust (=coarse) I use wheat flour. You know, the stuff for bread dough.
It is:

* Close to wood as a material.
* Much finer than wood dust from sawing or sanding, so creates smoother surfaces.
* Almost wood colour (light).
* Available everywhere.
* Very cheap.
* Ecological. When You need to get rid of the excess, just bake a bread and eat it.

Further hint:
If You need to match filler colour to wood colour, try using other types of flour also: rye, barley, corn...
And try colouring it with ground cinnamon, ginger..."

It is not immediately obvious from googling what the precise size range one sees in a bag of flour, but it's not an expensive material to work with. You probably want to use cake flour, which is more finely milled than bread flour. Cake flour (and pastry flour) may also be called soft flour, while bread flour is called hard flour. In France, cake flour is T45, in germany, it's 405, in Spain, no idea.
[en.wikipedia.org]

Telling them apart:
"
Bread flour feels course when rubbed between the fingers. If squeezed into a lump in the hand, the lump falls apart. It color is creamy white.

Cake flour feels very smooth and fine. It stays in a lump when squeezed in the hand. Its colour is pure white.

Pastry flour feels smooth and fine like cake flour and can also be squeezed into a lump. However, it has the creamy color of brad flour, not the pure white color of cake flour."
- 'Professional Baking' by W. Gisslen

Particle size:
[pharmacy.wilkes.edu]
According to the link above, flour is 50 to 100 um. I assume the writer is refering to cake flour.

Particle shape:
[www.umanitoba.ca]
Soft wheats apparently get crushed into slivers when they are milled, whereas hard wheats form more equi-axial shapes. (This may be why cake flour stays in a lump shape when squeezed, while bread flour falls apart.)

Other filler materials
What about marble dust? aka Calcium Carbonate powder.
It seems to be a traditional epoxy filler.
[cgi.ebay.com]
Art supply stores may have it as well.
[www.dickblick.com]
It's used in construction if we ever need it in huge quantities.

Thanks for all the input.

maybe I should explain a little better what I have tried allready and what I'm aiming for:

I have allready tried starch and it has no effect as a crosslinker. I'm working with a brittle resin, wich os fantastic for hardness, but needs some kind of filler that crosslinks the polymer and has some flexible properties.

Starch cannot do this as it's a crystalline type of multiple sugar molecules, but not enough of them to constitute fibers. I have trie dthis and it didn't yield any different results than the resin all by itself, except that it slows down the reaction time quite a bit. I haven't tried flour, but I expect it to function along the same line as starch. The bonding properties of regular flour depends on its gluten conten, a natural protein that swells and bonds in a network with water. Maybe trying integral flours would give a better result, i coul try that: it's cheap and readily available. Thanx for the idea!

Mineral dusts, as Titanium Oxide or Kaolin (or marble dust) work really well as stabilizers and specially the first one seems to give the finished resin some added chemical stability. These will definitely be a part of my final mix to give the whole chemical stability and thermic inertia, wich are great features to have. They also cheapen the resin mix drastically.

What I need now is some kind of fibrous material that will add flexibility to the mix. I could do this by adding several monomers (eg butadiene, or complex chemical crosslinkers), but finding a filler that does the same trick would cheapen the final mix a lot. That's why I'm aiming at cellulose powder. I think I will go and have a look at animal shops or nutrition shops. They should have fine ground husk powders or cellulose powders that woul do the trick...

Thanx again for your ideas!

Be careful. You're the chemist, so you probably already know this, but I can think of another potential use for cellulose that would make a lot of people nervous.

Hi Fernando,

... try coffee-powder - it's common and you can define the granulity by the time it's milled.

When it's not enough interconnecting, then you can use all kinds of fibre-holding vegetables smashed to powder in a coffee-mill

Viktor

How about baking soda? It's definitely cheap. In bulk, it's about $2 per kg. Not exactly fibrous, though, and it might do odd things if the resin's acidic.

This place seems to have relatively cheap bulk baking products (e.g. 50lb of corn flour for $42.99): [store.honeyvillegrain.com]

Starch? Hair? fiberglass insulation? yarn shavings cut up really fine?

Ideas only

Demented

A major issue with fibers is that they are resin hungry materials. If you want flex in the material add polyurathanes. Most two part polyurathene casting resins sold at craft stores are straight chain polyols so they have relatively high molecular weights to hydroxide values. The furfural with react with the polyol so you wont even have to use the isocyanate.

Also detergents or soaps are going to add a great deal of flex to the system with relatively small additions, they will also stabilize an emulsion if you want to add heavier oils for even more flex, or if you want to try some water based additives. And since most commerical detergents are weakly basic they should further stablize the blocking agent on the cataylst. The water will tend to slow the dehydration reaction of the furfural but that can likley be formulated around.

Soaps and detergents are also heavily ionic in nature and so should assit in lowering the resistance of the end traces.

Mike

The thoughts expressed in this post are my own and do not reflect those of my employer. Any attempt at implementation is at your own risk.

Have you considered using powdered fibre-based or "volume enhancing" laxatives like musilex or any psylium based product? As Mike pointed out it won't enhance flexibility but it might increase toughness by as part of a composite material.

I will try regular flour and then some fiber food additives like the ones you mention (psylium, oat fiber and other mucilagens), just to learn the effectiveness of these so called water soluble fibers.

Actually I'm very positive that cellulose fiber, wood dust and some other plant derivates will help me as they contain the right kind of fiber. What I was wondering is if anybody had been working with a readily available source of some fiber product that I wasn't aware of.

I also know that glass fibre would be an excellent additive, but I wanted to try with something cheaper and I though easier to get by and less itchy. If none of the flours or oat fibre works or if I can't find a provider of large packages of cellulose fibre at cheap prices then I'll go for chemical crosslinkers.

Thanx to all for your input

Hi Fernando,

... i actually 'played' a bit with Natronwaterglass (water-soluble Alkali-silicate) and glass-dust.

It seems to work as hoped - in the bottle/syringe it stays stable, on air it will dry in some minutes to nearly solid and with a H2O2-microflame i melted it without problems to solid glass - and there will only water fume out.

At home i'll try with some other dusts and powders if it's possible for metall- and conducting pastes too ...

Viktor

Found some bulk proiders here:

The cellulose fiber is called SANCEL
[www.nbent.com]
it's packaged in 25kg bags

It's the same stuff you can buy at a nutritionist:
[www.amazon.com]
only that the nutritionists 250g costs you 6$

I'll try that as a filler too.

... first experiments with waterglass showed, that it's a perfect soluble/fixing for glass- and ceramic-dust, as it dries on air in minutes to a solid matrix, stiff enough to support aditional layers and could act as ready-to-use moulding-form without further curing or heating ...

Baking in an oven cure the body to maximal stability - i didn't try with melting of soldering glass at higher temperatures, but this could be interesting, when the waterglass-matrix could stabilize the body, so it wouldn't melt away ...

For coarser powders and additives it's not so clear - sometimes i received fuzzy results, as the homogenity of the solvent may change when heated, so some parts will harden very good, other stay fluid or develop cavities.

I didn't try with conducting materials, here it's possible, that the waterglass forms a stable mesh between the metall-particles, so they didn't form homogene conducting chains as needed ...

Viktor

You can get oat fiber for as little as $2.10/lb - if you are willing to buy it in bulk.

nettrition.com 244-0004 LifeSource Foods Oat Fiber 500 1 lb. (454g) $3.29

frontiersurvival.com FR10-051 - Oat Fiber 4 LB $11.97

honeyvillegrain.com Oat Fiber 50 LB Item Number: 55-050 $104.99 2 $209.98

Another source of inexpensive short fibers is dryer lint. After each time you dry clothing, some of the fibers break off and get trapped in the lint filter. With modern fabrics, you are talking mostly polyester. Cotton would be good if you could get it small enough.

Mike

How are you mixing your polymer and filler eg flour/starch etc?

The dispersion of the filler in the bulk is as important as the filler its self.

what resin are you using, i.e. what is your base matrix material.

Carbon nanotubes are excellent toughening fillers, I have experience using them. But I don't think they are cost effective for this application

... using carbon nanotubes can result in same problems as with asbestos, as they're fine enough to penetrate every filter and the biological implications aren't researched clearly

When last tried, i used glass, stone and alumina microspheres (solid and hollow) in waterglass or polymer - the mixing isn't the problem, but the solid microspheres can sediment and the hollow ones can float up, so the density or dispersion of the solidified material can change with the needed curing time ... even when the initial dispersion was uniform

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Viktor
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I am looking out for a procurement of ground nut husk in our factory near Karad ( Maharashtra )
Off take would be regular and larger. Any body can suggest is there any agency who can do it ?