As previously mentioned, Habib Saidane has posted a video of his new process using CMC and Ferric ammonium citrate as the photosensitizer:
So I started thinking what else could we use as sensitizer. I found that Sodium Benzoate is cheap and could be a photoinitiator so I started testing it yesterday. Indeed, there’s a reaction with UV light. I don’t want to share amounts yet because I’ve barely started looking into this. But I was certainly able to change the solubility of CMC. The reaction is similar and suffers from the same oxygen inhibition that the citrate and oxalate from the Chiba process suffer. Yesterday I tested adding an acid. It turns out that if you add an acid, you create benzoic acid in the mix which can then absorb UV light. In my test I setup a bunch of samples with varying UV exposure and chemical mixes, and as you can see there are some clear winners where the stuff completely dissolved or stayed solid.
A few of the most interesting things about this experiment are the very nice mixing and suspension of carbon in the liquid and the shear thickening. The liquid glop almost becomes slime when adding acid and sodium benzoate. In some ratios, the shear thickening is crazy good. By itself CMC swells ridiculously.