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Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...)

Posted by spota 
Re: Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...)
November 27, 2007 05:14PM

Maybe these Alkali silicates will help you lower down the fusion temperatures of your ceramics? this is what in German would be called "Fliess Mittel".

I know that for this purpose Postassium Carbonate, Sodium Carbonate, Lead Carbonate are being used in the glass industry. My chemists gut feeling tells me that Alkali silicates should lower the melting temperatures down to more sensible values.

Keep me posted, I'm very curious about ceramic sintering as a promising repprap process!
Re: Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...)
November 27, 2007 06:13PM
I've heard of someone repairing an engine block with waterglass. I don't know if he was successful, but that was his stated goal when he purchased it from my mom.
Re: Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...)
November 28, 2007 01:48AM
... i have a ceramic-paste called "Karger keramische Vegussmasse", which dries at room-temp to a hard to remove but brittle solid and can be cured in the oven to behold a bit better, but stays brittle too.

I think, it's simply ceramic-dust wuth waterglass too!

We used this paste for embedding and covering high-temp-sensors for 500
Re: Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...)
December 01, 2007 04:37AM
I have to give credit to whomever told me to try regular flour!
I made a batch 2 days ago and left it to polymerize with straight catalyzer, no blocker.

here are the figures:
4 grams of flour
4 grams of Furfuryl Alcohol
1 gram of catalyzer solution (40% pTSA in a common alcohol sovent)

The result, as I saw them today are a flexible yet tough black polymer. Comparable to, say, shoe sole material! That's an unexpected result for me as I thought that flour containing only 11% gluten would not be good enough to add these features to the mix. But it did!! I was a foo not to believe! smiling smiley
And it also had the effect of chemically stabilising the FA, making it safe to mix with non-blocked catalyzer.

I think that varying the load of flour and adding a mineral dust, like Kaolin, Titanium Oxide will yiel a series of polymers from hard and brittle to soft and pasty.

Gotta go!
Re: Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...)
December 05, 2007 03:28PM
Try mixing the catalyzer into the flour first, partially fill a pan with the resultant mixture, and then using a syringe write a pattern in the pan with FA, add another layer and repeat. I would be very interested to see if you have any interlayer adhesion issues and what your surface finish is like on the finished piece.
Re: Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...)
December 11, 2007 04:38PM
Hey all!

I will continue my this thread under the Gooey Extrusion sub-forum as it seems a more appropriate place to talk about... well, gooey stuff


See you over there!
Re: Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...)
March 09, 2010 07:06PM
Wow it feels great to be back!

Wonderful to see that you have kept after this side of things.

Since the Furfuryl reaction is a dehydration reaction one of the easiest ways to slow things down is to add a little water or even a mild base since when the blocking agent comes off of the catayst the resultant acid will be bufffered. That allows you to not starve the individual areas of the build while still controling the reaction rate.

I have been thinking that maybe the best way to do this would to inject small amount of unblocked catayst onto a just extruded paste containing furfuryl, the blocked catayst and a filler. You might be able to use the reaction heat from the furfuryl and the unblocked catayst to activate the rest of other catayst(s). The sustained heat would also dry out the furfuryl and push the reaction towards completion.

I had also been thinking that blocked catalysts with different unblocking temps could be dripped over a just extruded paste of Furfuryl and filler would allow for the very slow heat up and dehydration. There is a commerical system that uses a bed of filler(sand usally) that is coated in unblocked catayst and then the liquid furfuryl resin is sprayed over-top of it. The filler bed indexes down slightly and a fresh layer of filler is added on top to allow the process to continue. It's used to produce foundry sand cores and works wonderfully.

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