[mikeynzb]

http://www.google.com/patents/EP2054128A1?cl=en

[khemnoob]

Hi, did anyone have any success at this? I am now in the possession of play sand, PDMS, and boric acid, and would love to have a place to start!

[Furanone]

I am guessing it is a viscosity issue and the highest viscosity sample you have of the two is not nearly high enough. Your sample is probably too oily where the polydimethylsilxoane (PDMS) will actually rub off on your hands. To avoid this you need a much higher molecular weight (MW) sample of PDMS, that will bind the sand all together and not 'leak' out. Check out the link provided below for PDMS to see all the varieties you can purchase that differ only in MW (and perhaps MW distribution).

There is a clear relationship between the molecular weight of the PDMS and its intrinsic viscosity based on the Mark-Houwink equation [n]=KM^a. From my calculation using the data from the website link, I get intrinsic viscosity [n] = 0.00005653 x MW^0.7382 (R^2=0.9955). Therefore I estimate at 2% PDMS in 98% sand, you would likely need a MW of around 800,000 Da (Int Visc of 1.8 dl/g) for your kinetic sand to be successful.

link:
http://www.ampolymer.com/Standards/PDS.html

[Furanone]

Yes, reading some of the other posts now. Adding Borax (Boric acid as sodium salt) could have a similar effect as just using a higher MW PDMS provided the PDMS has free hydroxyl groups (hydroxyl terminated) since the cross-linking occurs at four closeby -OH groups.

This will in effect increase the working MW and viscosity as just using a higher MW PDMS. The key here will be getting the ratio of PDMS polymer and boric acid just right since too little will still leak oily residue out of the sand while too much will make it a hard sand mass that will have no pliability.

[GJ610]

Hi, I've looked online and found a pdf giving instructions on how to make the kinetic sand, link as followed (http://www.chymist.com/Kinetic%20Sand.pdf), in the pdf it says that you need to use super fine sand, and drying the sand for several hours or overnight at 120°C.

[Arkcon]

The author's whole website is here:  http://www.chymist.com/toy_store.html  And it looks like its all fun.

[Benjamin]

Hi,

You must be trying to copy the "Kinetic Sand" invented by Delta of Sweden. Please remember that the MSDS does not tell everything. Kinetic Sand is 98% sand and 2% magic, where the ‘magic’ a bonding agent that causes the sand to stick only to itself in a soft clump. The 2% magic component may be an "organic boron-crosslinked polysiloxane." Note that the patent is still pending.

[Benjamin]

The bond(Si-O-B) is dynamic and reversible.

Please note that the key ingredient of Kinetic Sand would be polyborodimethylsiloxane (PBDMS) or polyborosiloxane (PBS) derived by a crosslinking reaction between organic boron compounds and polydimethylsiloxane (PDMS). The so-called "grab-release" mechanism of such "reversible bonds" (Si-O-B) results in the self-healing, energy absorbing, viscoelastic flow properties of silly putties and the likes. The original "Silly Putty" is based on the accidental finding by James Wright, an R&D chemical engineer, at GE in 1943! It is now commercially available from Dow Corning, Wacker, Shin-Etsu, Silikony Polskie, etc.

"Since boric acid is trifunctional, a single boron has the ability to join three polysiloxane chains together. This joining of chains is called cross-linking. Cross-linking produces a high molecular weight polymer that is a soft, pliable gum with very interesting chemical properties." (https://www.wou.edu/las/physci/ch462/BouncingPutty.htm)

Dr Phil Green at the University of Hertfordshire in Hatfield, now technical director of d3o Lab describes d3o foam material as, "An elastic cellular polymer containing transient dynamic cross links. (http://www.eurekamagazine.co.uk/design-engineering-features/technology/cross-links-cushion-impacts/2894/)

His further comments are:

"The material can be moulded into virtually any shape, which has enabled us to optimise the geometry for maximum conformity, flexibility and breathability for integration into garments. It can be either fabric backed for easy integration into clothing or moulded into discrete components. We currently supply a polo company, Casablanca, with moulded inserts for their polo knee protectors.

"We have a number of automotive applications we want to explore, such as suspension bushes, pillar liners and sound insulation. Although the cost is not prohibitive and will come down with volume production it is a premium material that is high value add and not a commodity sheet material, although we are looking at continuous sheet production for the near future. The raw materials are not commercially available and have been formulated to our specification.

[skovi]

hi there,

has anybody of you tried some of the receipts? What was the result?

I tried mixing very fine sand and dimethicone, but this is not the right way to go - I just got an oily sand - this is no way near to the kinetic sand - it behaves like a wet sand, but makes a less mess. If you use a high viscosity dimethicone, then you will have poroblem to cover each sand particle with it - i think that this method just does not work.

I also tried to add the boric acid to the process, but I find this tricky. Boric acid is solid - i tried to dissolve it in water and then mix the oily sand with the soluition and the mix it for hours while heating it - after a long process not much happend - I still have just an oily sand - the water has evaported.  I am trying to figure out how to mix dimethicone and the boric acid (make the silly putty) - do you have any ideas receipts how to make it at home? Do you dissolve the boric acid in water first ? what is the best way to dissolve the boric acid - do you heat the watter?

[Intanjir]

Have you tried cutting the too-high viscosity dimethicone with a lower viscosity solvent which can be evaporated out?
The goal is to make a thin coating here and commonly we use some kind of carrier liquid which is then evaporated.

As for adding boron in, water isn't going to work, you generally want a solvent that can dissolve/mix with all components.
Trimethyl borate might be worth a shot and isn't hard to prepare and is at least already liquid.

[Krip]

Did you find how to make kinetic sand. I tried mixing dimethacone with fine playsand. But it didn't work. I read this post just today. If anybody knows about it, please guide me. Thanks in advance.

[Krip]

I want to make kinetic sand at home using dimethicone. However, with the normal beach sand with 6% of dimethicone, I couldn't make kinetic sand and it didn't show any such property of kinetic sand (binding of grain together). Could you share more information regarding how to make kinetic sand like what is the grain size of sand? Is it just dimethicone or something else needs to be added to make it kinetic sand that we can get from the market? Thankyou