Lost in this all is the fact that nothing here seems to supply a means of hardening the polymer, but it does appear to have some properties that allow adhesion to the glass. Will it work on film support?
All this is way above me. I am a dentist and use silane as a coupling agent to coat porcelain restorations prior to bonding them to teeth with resin cements to enhance the bond. Using it with the emulsion to coat glass plates is probably works in a similar fashion. As a dental product silane is over $50 for 12ml.
Just thought this may be of interest.
Maybe a bit similar, from Wikipedia:
Originally Posted by jeffreyg
"Several industrial and medical applications exist for silane and functionalized silanes. For instance, silanes are used as coupling agents to adhere glass fibers to a polymer matrix, stabilizing the composite material. In other words, Silane coats the glass fibers to create better adhesion to the polymer chain. They can also be used to couple a bio-inert layer on a titanium implant."
"The nineteenth century began by believing that what was reasonable was true, and it wound up by believing that what it saw a photograph of, was true.
" - William M. Ivins Jr.
"I don't know, maybe we should disinvent color, and we could just shoot Black & White.
" - David Burnett in 1978
"Analog is chemistry + physics, digital is physics + math, which ones did you like most?
It is quite possible that, in my recent emulsions, the formalin just sat there doing nothing. However,last night I did a quick search of crosslinkers for PVA. I not only found refferences to formalin and glyoxal, but to borax and even to bromine salts. Rather than argue over it, I plan to do some experements. I will compare the water solubility of films made from Kuraray silane / PVA with and without formalin and some other components of the emulsion.
Yes, silane coupling agents are toxic. That is one reason to use Kuraray product instead of pure coupling agents. But I think that, for me, it is way too late to worry about it now. I started working with organo-silanes in 1974. I am careful, but time is time and quantity is quantity.
Actualy, adhesion to glass is the whole thing. Although silane groups replacing hydroxyls will decreace watersolubility. In another study, I replaced all of the OH with silane . The resulting polymer was totaly insoluble in water. The Kuraray polymer is fairly easy to disolve in NEAR BOILING water. So there must be relatively few silanes, relative to hydroxyls.
Originally Posted by T-grain
Unlike gelatin, a PVA based emulsion dose not "set up". It must be alowed to dry.
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Hi PE and All,
My first water solubility tests indicate that niether formalin nor glyoxyl will cause a film of the kuraray polymer to become insoluble in Hot water. Both films eventualy dissolved, totaly. But the dried film, and the emulsion, are very hard on the gl;ass plate. Very difficult to scratch the surface or remove the film from the glass. I know at least one emulsion maker who makes gelatin plates, and never uses hardener.
perhaps an interlayer of polydimethylsiloxane (polyvinylacetate) between the support and the silanized PVA could work?
Originally Posted by Photo Engineer
I can tell from first-hand experience that styrofoam (or another non-cellulose but porous material) could be easily glued together with PVA or PVAc wood glue
maybe the subbed support has just the right surface texture.....
Not to be arbitrarily negative, but why would you want to do that? The point of attaching silane groups to the PVA polymer is for good adhesion to glass. It realy dose work, and has been used for that purpose in all sorts of industrial application for many decades. As for PE's question about adhesion to film, IDK, and will let someone else find out. I live and breath glass. I wish that the entire planet and everything in it could be glass, and, like my heart,easily broken.
Beavis and Butthead???!!!. I realy would have expected better from you. At leat South Park, which is "High Brow" compared to B&B. Seriously," Dude"!
I was referring to PE's question about adhesion on film (where there's no silanol groups, but acetate etc. instead). And maybe such a layer could provide good adhesion for the silanol modified PVA (emulsion).
Originally Posted by wildbillbugman