plante1999
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PVDF substrate MnO2 anode
Today I have buy 1 feet of 1/2 inch PVDF rod , PVDF is somewath solube in acetone and , as a fluoro polymer it is very inert , it melt at 170 degree C
, I have atempt to make MnO2 by , taking a Manganese sulfate solution and adding 5% NaOCl , filtering the hydrous MnO2 and mixing it with acetone ,
then I rub the mixture on the rod , witch was coated with a sticked layer of MnO2 , when I was testing I found it was very restrictive for the current
, wat do I did wrong?
If you ave better idee than mine , or explication , please post.
thanks!!!
[Edited on 3-8-2011 by plante1999]
[Edited on 3-8-2011 by plante1999]
I never asked for this.
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#maverick#
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Try thermally decomposing manganese nitrate on to it. If current flow is still restricted then the mno2 might be passivating the PVDF. Try thermally
decomposing cobalt nitrate on to the rod prior to applying the mno2. This works very well with titanium.
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plante1999
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Wath is the temperature of decomposition of Manganese nitrate?
I never asked for this.
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#maverick#
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Wikipesdia it. Under 300 c I believe
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plante1999
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I cannot heat to 300degree C , the rod melt at 170...
I never asked for this.
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plante1999
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I attempted to melt the PVDF with MnO2 and , the anode is still non conductive , i need to sand paper it....
any sugestion?
I never asked for this.
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#maverick#
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Try with thermally decomposing a layer of cobalt nitrate. Prior to decomposing the mn nitrate on it
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White Yeti
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I'm a little confused.
"PVDF is commonly used as insulation on some kinds of electrical wires, because of its combination of flexibility, low weight, low thermal
conductivity, high chemical corrosion resistance, and heat resistance."
Why would you try to make an anode from a polymer material? No wonder your anode has a high electrical resistivity.
Am I missing something? There are a million other substrates you can use, why would you use plastic?
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m1tanker78
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Have you tried using the polymer as a binder rather than just the substrate for the MnO2 to stick to?
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plante1999
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because it is the only substrate I find at 20 minute of walk from my house and it is very inert , more than titanium.
M1tanker78 : No I dont have try but it cost my 10$ to buy 1 feet , so I dont want to destroye the rod.
I never asked for this.
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White Yeti
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The problem is that the thin film of manganese dioxide with have an extremely high resistance because of its very small cross sectional area coupled
with its already very high electrical resistivity.
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plante1999
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should I change for powdered lead acid battery PbO2 powder in place of the higly non conductive MnO2 , I have about 200 pound of Lead Acid battery ,
my fatter work with Pb battery , and keep the good for me....
thanks again for reply.
[Edited on 4-8-2011 by plante1999]
I never asked for this.
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White Yeti
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Powdered PbO2 is no good. there is no way to reliably deposit PbO2 powder on any surface whatsoever, electrically conductive or not. Usually PbO2 is
electrolytically deposited on anode surfaces. Alas, the surface needs to be ultra clean, rough and relatively inert, but this can still be done.
I'm trying to make MMO anodes as well. I found some transition metal oxides that might be used in such anodes, I thought you might be interested:
VO
NbO
RuO2
Co2O3
RhO2
I have yet to figure out which semiconductor oxides might also be useful for anode making.
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dann2
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Jasus lads!!!!!!!
The more I read this board the more I realizise the vast quantities of patience the regular posters have when answering queries.
@Plant1999
The coatings that you will put onto something plastic (non conducting substrate) by your method are far far too thin and will not be able to carry
sensible currents when the Anode goes into operation. The coating may not carry any current at all as the paste (Acetone + MnO2) is probably non
conducting.
Lead Dioxide Anodes made this way are a shitty Anode too.
Quote:
"because it is the only substrate I find at 20 minute of walk from my house and it is very inert , more than titanium"
Perhaps you need to buy a bicycle and go a mile or three!!!
EBAY comes to mind.
If you cannot use EBAY then go to your local welding shop and they may be able to order a sample of Titanium welding rods for you. These are about one
mm in diameter and will do for experimenting.
What happened with the Aluminum substrate Anode you made. Did it not last for weeks??? (I have me doubts but never mind). You never posted the
details.
Post the details.
I have not made that many Anodes, just talked about them alot 
@#Maverick#
You said:
"If current flow is still restricted then the mno2 might be passivating the PVDF."
Passivate PVDF!
If you say that again I will recommend you to the moderator who administers the Sciencemadness slaps, for (at least) 6 hard slaps!
Do you know what the statement 'passivated Titanium' means?
Dann2
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plante1999
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Wath about disolving PVDF in boiling DMSO (where can I optain this(DMSO)) to make syrup of PVDF (the same syrup they sell for making PVDF electrode.
Than thake a 3/8 inch straw an fill it with : fine MnO2 or PbO2 mixed with PVDF syrup and press a rod of 3/8 inch inside the straw to make a compact
conductive electrode/rod , lets dry the DMSO to get an hard rod , take a cutter and cut the plastic straw ? Than make electrolitic coat of MnO2 or
PbO2 on the rod?
@Maverick
You said:
"If current flow is still restricted then the mno2 might be passivating the PVDF."
1: PVDF is an EXTREMLY INERT fluoro polymer.
2: Passivate mean coat a conductive material with an non conductive one (exemple : TiO2 for titanium.)
3: PVDF is already non conductive....
@everyone
If you want to find PVDF rod simply search for a plastic store near your home , ask for PVDF rod ?/8 inch dont ask more than 2 feet or it will cost
you high amount of money.
[Edited on 4-8-2011 by plante1999]
[Edited on 4-8-2011 by plante1999]
[Edited on 4-8-2011 by plante1999]
[Edited on 4-8-2011 by plante1999]
I never asked for this.
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dann2
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Quote: Originally posted by plante1999  | ........ Than thake a 3/8 inch straw an fill it with : fine MnO2 or PbO2 mixed with PVDF syrup and press a rod of 3/8 inch inside the straw to make a
compact conductive electrode/rod ,........
[Edited on 4-8-2011 by plante1999] |
This rod will not be conductive as the plastic syrup will insultate each individual particle of MnO2 or Pb02 and you just end up with a non-conducting
rod.
Try it and see. If it works I will eat my boots!!
Dann2
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White Yeti
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I'm with dann2 on this one.
Although, it would be interesting to see him eat his boots 
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plante1999
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Where I can find DMSO? , Even if I ad only a little of PVDF syrup it will make all the rod non conductive? In fact I want to make a PVDF substrate
because it is for Chlorate/bromate/ozone cell particuliary for examining the possibility to replace nitric by chloric or bromic acid , So I cannot use
titanium.
Any idee here about PVDF substrate anode?
thanks!!!
[Edited on 4-8-2011 by plante1999]
[Edited on 4-8-2011 by plante1999]
[Edited on 4-8-2011 by plante1999]
I never asked for this.
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plante1999
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Nobody kow something about tha last post i made ? (Where I can find DMSO)
I never asked for this.
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White Yeti
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Why bother using DMSO? Just get a titanium electrode and start plating metal oxides onto it. There is no reason what so ever to use plastic to make an
anode.
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plante1999
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| Quote: Originally posted by White Yeti | | Why bother using DMSO? Just get a titanium electrode and start plating metal oxides onto it. There is no reason what so ever to use plastic to make an
anode. |
| Quote: |
In fact I want to make a PVDF substrate because it is for Chlorate/bromate/ozone cell particuliary for examining the possibility to replace nitric by
chloric or bromic acid , So I cannot use titanium.
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I never asked for this.
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m1tanker78
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I recall reading about some varieties of conductive thermo-plastics. I can't find the info ATM but I pondered the use of such a polymer for binding
lead dioxide (any conductive oxide, actually). I expect the electrical resistance would initially be rather high but that can partly be overcome by
using a larger cross-section of material.
I've had very satisfactory results with my chlorate cell using plain old graphite gouging rods and frit filtration. The anode can be made to last a
long time if you keep the pH in a narrow range, use proper current density, temp, etc...
As far as DMSO, I'm almost certain one of the member [external] websites had a detailed synth (bromicacid?)
Tank
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