rooster - 26-10-2003 at 09:23
I am wondering if anyone has made PVN (polyvinylnitrate). It sounds like an interesting compound, and with many different VoD's. It is made from
polyvinylalcohol. The molecular weight can be very different, and this is what affects the density and VoD.
Anyone tried this compound? If so, with what molecular weight of the PVA?
palpy - 26-10-2003 at 09:28
well, it's a nitric ester, so i guess that the VoD varies due to the meta-stabile detonation...
Haggis - 26-10-2003 at 09:44
I am not sure about the molecular weight of PVA. Since it is a polymer, there should by no specifice molecular weight for it. I believe I read some
place that they havn't yet seperated a vinyl alcohol monomer, so that kind of leaves you in the dark.
rooster - 26-10-2003 at 23:54
I have seen PVA with molecular weights from 10.000 to 100.000. The 100.000 is the most dense I have found, but I bet you can find even heavier PVA.
Meta-stable detonation? What does this mean?
I think the VoD is affected by the density, PVA 100.000 is more dense than 10.000, and I think thats why the first one's nitrate has a higher
VoD.
What leaves me in the dark??? Didn't quite get this. I am not looking for the monomer. The polymer can be found/bought with different molecular
weights.
Theoretic - 31-10-2003 at 06:26
I think you can use straight polymer to make PVN. I suggest:
1)Dissolve PVC in a polar organic solvent (it has to also dissolve NaNO2, hopefully acetone does - the web didn't give me the answer).
2)Dissolve NaNO2 in that.
3)Heat in a water bath (be sure to prevent evaporation of your precious - and toxic - solvent - seal or what).
4)Very probably NaCl will fall out as insoluble precipitate.
5)The reaction formula is this: [C2H3Cl]n+n NaNO2=>[C2H3NO2]n+ n NaCl.
6)Then let the solvent evaporate. That leaves you PVN!
For [C2H3NO3]n you could use NaNO3 (it's only slightly soluble in acetone though).
palpy - 31-10-2003 at 10:01
liquid nitro-esters have meta-stable detonation - it means that their VoD depends on the strength of initiation (flame, cap with only primary, cap
with some HE, booster charge)
theoretic: [C2H3NO2]n is not polyvinylnitrate but polynitroethylene (and could also be polyvinylnitrite, if it exists)
PVN is that [C2H3NO3]n
[Edited on 31-10-2003 by palpy]
Iv4 - 2-11-2003 at 05:20
What if NaNO3 were used?
Preparation of PolyVinlylNitrate (Patent Translation)
chemoleo - 11-11-2003 at 17:43
Here we go, I found a German patent on the preparation of PolyVinylNitrate:
Patentschrift 537303
Darstellung von Polyvinylnitrat, 14/10/1931 (--> it's old!!)
Significant Excerpts (translated), question marks indicate my own interpretation
Normally Polyvinylalcohol oxidises upon nitration. This is not so, however, if it is first sulphonated with H2SO4 (conc). Then, after nitration,
polyvinylnitrate separates from solution as solid soft chunks or as a gluey sticky mass. It explodes (after washing with the appropriate agents for
removing acid (though not mentioned, prob. bicarbonate)) by a strong blow (such as a hammer blow?) or by heating it strongly (no details on
temperature given).
Preparation (more or less directly translated):
40 parts of polyvinylalcohol (pulverised - although I wonder if that's necessary, providing thorough stirring is done) is added to H2SO4
(concentrated, presumbably >96%, although it is not explicitely stated) in small amounts, while keeping the temperature at around zero degrees
Celsius. It dissolves slowly and is thoroughly dissolved after 1-2 hours, causing a significant increase in the viscosity of the reaction mixture
(H2SO4 and PVA). The solution (filtered from solid particles, presumbly after filtering thru a borosilikate filter) is slowly added to a nitration
mix, consisting of 930 parts of HNO3 (density = 1.48, which is according to BASF between 80 and 100 % (1.452 -1.513 g/cm^3)) and 1000 parts of H2SO4
(density = 1.84, 96% according to BASF). While stirring continuously, the solution is slowly heated to 45-50 deg Celsius. At that temperature, the
solution becomes rapidly turbid, and the polyvinylnitrate sequesters as sticky, plastic small or larger pieces. Then one filters the PVN rapidly from
the nitration mix and washes it in ice-cold H2O. The washing causes the PVN to lose some of its plasticity. One obtains 80 % of the theoretical
yield, with 10 % being nitrogen (feel free to calculate the degree of nitration yourself).
The resulting polyvinylnitrate is soluble in acetone, acetophenone, and pyridine.
(this possibly indicates a route to further purification).
The novelty of that patent appears to reside in...
1) first mixing the PVA with H2SO4
2) and the high yield of PVN being obtained by slowly increasing the temperature together with the nitration mix. As a result, the PVN sequesters, as
solid plastical (soft) chunks. As noted above, however, the plasticity decreases upon thorough washing with ice-cold water.
Questions:
1) Although I speak German perfectly well, I am not 100% sure as to what ' parts', or 'Teile', refer to. For instance, it cant be
the molecular mass as the molecular mass of PVA is undefined (being a polymer). Most likely it refers to the the weight as such, without reference to
molecular stoichiometries (in fact, volume wouldnt make sense, the only thing that makes sense is weight!!).
2)I am not sure where one could obtain polyvinylalcohole (PVA) over the counter.... but maybe I should search this before I raise this point)
3) No reference is made to the heat or strength of blow necessary to cause PVN to explode,
4) No reference is made to the degree of polymerisation of PVA that is desired - but maybe that's not a crucial parameter...
What do you think of this? It's a patent, so they obviously haven't been bullshitting!
Chemoleo
PS Send me a U2U if u'd like to have the german patent original
KABOOOM(pyrojustforfun) - 11-11-2003 at 21:13
thanks chemo
<a href="http://www.angelfire.com/rnb/pjff/pvn.zip">US2118487 reduced to 86.8 K
needs a TIFF reader (ACDSee works if u have)</a>
[Edited on 12-11-2003 by KABOOOM(pyrojustforfun)]