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wildbillbugman
06-20-2011, 07:39 PM
:cool:Hello To All
Several weeks ago I began evaluating a commercialy availible Silane Treated PVOH in substitution for my Homade Silane treated PVOH (That I have been substituting for gelatin in silver halide emulsions) Results are the best I have ever had, not only for silver-halide emulsions but as a carrier for Pt/Pd/Au/Pigment on glass. I have long known about these polymers,from the middle and far east, but have never befor been able to get a sample. Kuraray America is a Japanese company with an office in TX or IL. I here website is www.kuraray-am.com. They sent me a free 1lb sample of there R-1130,The higher viscosity of two viscosities availible. After making several simple emulsions, I will probablky never silane treat PVOH myself again.
Anyway, I made a small batch of panchro emulsion in which, instead of splitting, the batch into three parts AFTER precipitation, I split the ammoniacle silver solution into two parts. I then added S/Au, in the form of Steigmman's Solution to both halves. Then I added Sands SDE3008(green senstizing dye) to one half and SDA3057(red sensitizing dye) to the other. Interestingly, the SDA3057 turned Cyan (the objective) dispite the fact that no Iodine was present.
I combined the two halves and added formalin. Coated onto glass, about 6 mils wet thickness. The next day I exposed through red,green and blue separation filters. The sensitivity of the red exposed plates was only slightly weeker than the green and blue exposed plates.(BTW-The color of the emulsion itself is bright lavende).
I am very much incouraged.
If anyone is interested in more detale,ask and ye shall receive. I have no secrets.
Bill:cool:

wildbillbugman
06-20-2011, 07:48 PM
For clarification, I should say that the two halves of the ammoniacle silver/dye/steigmann's solution were added,one at a time to the Resin/Br/I solution under shear of 1200rpm.
Bill

dwross
06-20-2011, 09:13 PM
Congratulations! I love it! I am truly inspired by your scientific persistence and integrity and your artistic vision. Your bug macros are gorgeous. You're definitely in my 'cool dude' pantheon, sir.
:), d

holmburgers
06-21-2011, 12:30 PM
So, do I understand this correctly... you're not using gelatin at all?

wildbillbugman
06-21-2011, 03:59 PM
Yes,
That is correct. Not a mg. of gelatin.
Bill

holmburgers
06-21-2011, 04:03 PM
That seems quite incredible to me. I'd love to know more, but I just don't know what to ask. Perhaps I will after the emulsion workshop...

Photo Engineer
06-21-2011, 04:19 PM
Bill;

How did you harden it?

PE

wildbillbugman
06-21-2011, 09:23 PM
PE,
Formalin. But I am not convinced,yet, that any hardener is required. HOT water will soften the emulsion, or hot water will soften a solution of the polymer in waster,after drying on glass. But when cold it is hard and virtualy imposible to get tthe solution or an emulsion made of this polymer off glass.

Bill

Photo Engineer
06-21-2011, 09:49 PM
Bill;

From my days coating PVA, I remember that it is not noted for being hardenable, so another site must be present. We used to add other active sites for hardening. I wonder what the reaction might be. Nothing occurs to me OTOMH.

Thanks.

PE

T-grain
06-22-2011, 03:20 PM
Bill, that thing you started looks very interesting to me! If you can share some more details about, I would be more than glad! I have a question though: did you use the silanized PVOH just for a better adherence to glass, or also due to its (somewhat) different properties compared to plain PVOH? At which temp does it set?
thanx in advance

T-grain
06-22-2011, 03:27 PM
Ron,
couldn't be PVOH hardenable (at least in an alkaline medium) by using boric acid? Or perhaps using glutaraldehyde?
regarding its mechanical/optical properties, does it differ much from gelatine? were there any attempts for using PVOH in photo emulsions?
since there are also some PVA variants available functionalized with anionic (and cationic) groups, couldn't be that stuff hardenable by just adding an aluminium salt?
thanks

Photo Engineer
06-22-2011, 03:49 PM
It is more common to use Acryl Amide, Poly Vinyl Pyrrolidone or Butvar in emulsions, and none of these nor Poly Vinly Alcohol resemble gelatin in any way. Gelatin has a structure which is imposed by its protein makeup. The amino acids act to peptize gelatin and it can chill set and crosslink. The others can, but under conditions often harmful to the silver halide grains.

The Silanes probably add something to the mix to improve the activity of the vehicle with the AgX crystals. IDK. It also may supply hardening sites. We usually used a site with an active methylene on it so that we could harden.

I've worked extensively with polymers in order to replace gelatin. It is not an easy task. I await Bill's results.

PE

T-grain
06-22-2011, 04:08 PM
Ron, what do you mean with a site with an active methylene-on which polymer? gelatine?
so PVP could be a "lousy" substitute for gelatin?
I am also very curious about Bill's results!
thanks

Photo Engineer
06-22-2011, 05:37 PM
Gelatin has active cross linking sites that work with formalin or other hardeners. These are amine based. Other active sites which can be placed on polymers are -C=O CH2 C=O (this is hard to draw and explain). In any event, Poly Vinyl Alcohol by itself is difficult to harden and has no sites to peptize Silver Halide grains as they form.

Therefore, something else (Silane?) is helping Bill. I am curious as well.

PE

Kirk Keyes
06-23-2011, 12:36 AM
It is more common to use Acryl Amide, Poly Vinyl Pyrrolidone or Butvar in emulsions,

Butt-Head: Whoa, huh huh, he just said "Butvar!"
Beavis: Yeah, Heh heh heh eh eh eh heh heh heh.

Sorry...

Kirk Keyes
06-23-2011, 01:15 AM
Silanizing agents attack compounds that contain hydroxyl groups by displacing the alkoxy groups on the silanizing agent and forming a covalent -Si-O-Si- bond.

It seems to me reacting a silanizing agent with Polyvinyl Alcohol will just add the silane to the alcohol groups - it will add mass to the PVOH chain, but not crosslink anything.

Also, to those reading that don't have experience with silanizing agents, they are kind of nasty compounds. You need to take real care when handling them. They are toxic through contact with skin and corrosive - that is they react with your skin as well.

T-grain
06-23-2011, 02:51 AM
Kirk, actually we don't know how the PVA (in this case) is derivatized, crosslinked or not. The Kuraray site states that it has silanol groups. therefore, these are probably more or less Si-OH groups which can interact with glass surface by hydrogen bonding SiOH......HOSi and of course within the polymer itself
I have first-hand experience with silylating (mostly trimethylsilylating to be precise) agents, since we use them in our lab for GC work. They are really useful stuff (greatly extend the volatility range of coumpounds), but yes, they are really nasty to work with.

Hologram
06-23-2011, 03:51 AM
Kirk, actually we don't know how the PVA (in this case) is derivatized, crosslinked or not. The Kuraray site states that it has silanol groups. therefore, these are probably more or less Si-OH groups which can interact with glass surface by hydrogen bonding SiOH......HOSi and of course within the polymer itself
I have first-hand experience with silylating (mostly trimethylsilylating to be precise) agents, since we use them in our lab for GC work. They are really useful stuff (greatly extend the volatility range of coumpounds), but yes, they are really nasty to work with.

It's been made probably along these Kuraray's patents: US 4617239 and US 4567221.

Kirk Keyes
06-23-2011, 09:39 AM
I have first-hand experience with silylating (mostly trimethylsilylating to be precise) agents, since we use them in our lab for GC work.

Same here.

What GC stuff do you do? I run air for volatiles with GC/MS (TO-15) and various drinking water and waz waste methods for water and soil with ECD or FID detectors.

T-grain
06-23-2011, 09:56 AM
Same here.

What GC stuff do you do? I run air for volatiles with GC/MS (TO-15) and various drinking water and waz waste methods for water and soil with ECD or FID detectors.

As for silylation, we do mostly aminoacids and other similar stuff (cannot disclose everything, sorry ;) ). Otherwise, we do mostly food and pharma analyses, a wide array.