Hello,
I am creating a slurry for ceramic 3D printing. I will be using silica (400nm particle size) as my ceramic material. Within the slurry, I will add a binder, a dispersant, and water.
I am currently looking into Ammonium Polymethacrylate (DARVAN C-N) and Ammonium Polyacrylate. I am not sure on how to select the proper dispersant as well as the proper amount to use. I am not relying on the dispersant to modify the rheological properties of the slurry, as the binder will help with viscosity, but rather that the silica particles are properly dispersed.
Any help is greatly appreciated!
Thank you!
Sam Choppala Thank you for your interesting question. Take a look at this webinar (registration needed) for a general approach:
Dispersion and nanotechnology
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W190528DispNanoMat
Hi there! Its all about DLVO theory! You have to balance the forces between electrostatic/electrostatic forces and Van Der Waals attraction. Your particles are a decently large primitive size for 3D printing which means that the lower total surface area might make it easier for you to control/stabilize the slurry suspension. The best way to test the proper amount of dispersant to use is empirically, by adding small increments to your suspension, mixing thoroughly between each round, and giving it a little time to settle/interact before adding more. As far as choosing the best type of dispersant— start with focusing on the charges you need to stabilize for what type of interactions you observe in your silica. We have also found that shorter polymer chains, with lower molecular weights, and higher charge potentials, are more effective in stabilizing suspensions. We work with calcium phosphates but have had success by combining a polymeric chain (with two-tailed functional groups) dispersant and a nonionic monomer to effectively stabilize the suspensions. One thing to keep in mind— how the water is playing a role in the interactions that are occurring with your suspensions. Once we started using the correct dispersant and monomers we decided to remove the water from our suspensions because it began to destabilize the suspension. I haven’t worked with Silica but I am familiar with the dispersants you are considering and think they might be good choices but it is worth verifying with the literature.
Dear Sam Choppala, better to think on the best stabilization strategy. It seems that surface modification by grafting special chemical groups gives the highest long term stability. It is to recall that NPs size, surface charge density, and pH are the main factors working on/against prolonged time stability. My Regards
https://doi.org/10.1016/0021-9797(71)90203-7
doi:10.1007/s11051-010-0085-1
That goes far beyond the DLVO theory in the presence of a polymer binder. Check our studies on polymer-nanoparticle dispersions:
Article Phase diagram of bare particles in polymer nanocomposites: U...
Article Thermodynamic Parameters Controlling Nanoparticle Spatial Pa...
Article Bulk Polymer Nanocomposites with Preparation Protocol Govern...
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