Newsgroup: it.scienza.chimica
Titolo: Napalm

Salve a tutto l'NG.
Qualcuno è in grado di dirmi con precisione che cosa è chimicamente il
NAPALM.
Grazie

 NAPALM.
NAPALM sta per NAftato-PALMitato, miscela di idrocarburi a lunga catena
che si aggiunge alla benzina (eptano-ottano) per renderla viscosa e
farla aderire dove la butti.

farla aderire dove la butti.
In effetti non e' solo cosi': il gelificante contiene sali di
alluminio degli acidi grassi (cioe' acidi carbossilici derivanti dagli
idrocarburi a lunga catena), che una volta dispersi si infiammano
immediatamente. Viene usato per costruire bombe incendiarie dai
terribili effetti, e per alimentare i lanciafiamme. Io conosco
un'altra etimologia: NAtrium PALMitate, palmitato di sodio (usato
all'inizio, prima della sostituzione con quello di alluminio).
Robby
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anch'io conoscevo questa etimologia.
ma i sali di alluminio non si infiammano servono solo a gelificare la
benzina. Ai corsi dell'esercito lo chiamavano sapone di alluminio. Le bombe
contengono un dispositivo (spoletta) ritardante per far si che ci sia una
dispersione prima dell'esplosione.
ciao
andrea

 all'inizio, prima della sostituzione con quello di alluminio).
da 
http://tchester.org/fb/issues/napalm.html
 copio e incollo:
--------------------- begin C&P
"Napalm" is actually now a general term for jellied gasoline. There are
many prescriptions for how to jelly the gasoline, and hence the
resulting products can differ dramatically. In particular, napalm made
poorly or with incomplete mixing can end up being very similar to
gasoline, with its attendant hazards. 
Gasoline, being a volatile, easily ignited compound with a high energy
density, was immediately used as a weapon in war. In World War I, both
Germany and the Allies used it in flame throwers, but it burned itself
too quickly to be very effective at igniting the target of the flame
throwers. As you might imagine, intensive research to slow down the
burning was funded by the U.S. government, and in 1942 Harvard
University scientists and the U.S. army chemical warfare service found a
way to jelly gasoline that worked quite well. 
They found that mixing an aluminum soap powder of naphthene and
palmitate (hence na-palm), also known as napthenic and palmitic acids,
with gasoline produced a brownish sticky syrup that burned more slowly
than raw gasoline, and hence was much more effective at igniting one's
target. The napalm was mixed in varying concentrations of 6% (for flame
throwers) and 12-15% for bombs mixed on site (for use in perimeter
defense). 
This mixture was a big hit with the allied forces, who used it
extensively in World War II in flame throwers and fire bombs. Half of
the bombs that rained on Dresden were napalm (incendiary) bombs. Napalm
bombs burned out 40% of the area of Japanese target cities. In the
Korean war, 165 gallon napalm bombs were dropped on enemy troops, with
very ffective "results". 
Popular weapons continue to be refined and developed, of course, and
napalm was no exception. With many more compounds available after World
War II, a safer and just as effective napalm compound was developed.
After all, gasoline is a pretty nasty substance, and of course is
extremely flammable (see below). The safer napalm is known as
"napalm-B", uper-napalm, or NP2, and it uses no napalm at all! Instead,
polystyrene and benzene are used as a solvent to solidify the gasoline. 
Napalm-B has a huge advantage over the original napalm - its ignition
can be well controlled. Hence soldiers smoking around napalm-B face no
hazard at all. (I'm told that workers at the Fallbrook Naval Weapons
Station used napalm to put out their cigarettes!) Yet a reliable igniter
can be used to start napalm-B burning exactly when you want it to do so.
Since the military would much prefer that the napalm burn opposing
forces rather than their own forces, the military quickly adopted
napalm-B, and it was this form of bomb-grade napalm which was used for
aerial bombardment in Vietnam and which is currently stored in
Fallbrook. 
The above information comes from the Encyclopedia Brittanica article on
napalm, and from Scott E. Harrigan, who kindly provided me with
information about the various types of napalm as described in Incendiary
Weapons by Malvern Lumsden. 
--------------------------- end C&P
ciao 
B.