Blowing up medieval gunpowder recipes

Date:
September 22, 2021
Source:
American Chemical Society
Summary:
First used for battle in China in about 900 A.D., gunpowder spread
throughout Eurasia by the end of the 13th century, eventually
revolutionizing warfare as a propellant in firearms and artillery.

Meanwhile, master gunners tinkered with gunpowder formulas, trying
to find the ideal concoction. Now, researchers have recreated
medieval gunpowder recipes and analyzed the energies released
during combustion, revealing that the evolution of the perfect
powder was a slow, trial-and- error process.



FULL STORY ========================================================================== First used for battle in China in about 900 A.D., gunpowder
spread throughout Eurasia by the end of the 13th century,
eventually revolutionizing warfare as a propellant in firearms and
artillery. Meanwhile, master gunners tinkered with gunpowder formulas,
trying to find the ideal concoction. Now, researchers reporting in ACS
Omega have recreated medieval gunpowder recipes and analyzed the energies released during combustion, revealing that the evolution of the perfect
powder was a slow, trial-and-error process.


========================================================================== Although largely obsolete in modern weaponry, gunpowder, also known
as black powder, is still used in historical weapons, fireworks
and pyrotechnics. The explosive is a combination of varying ratios
of potassium nitrate (or "saltpeter"), sulfur and charcoal. Medieval
recipes sometimes included interesting additives, such as camphor,
varnish or brandy, with obscure purposes. Dawn Riegner, Cliff Rogers and
their team of chemists and historians wanted to analyze the energetics
of medieval gunpowder recipes to help understand the intent of master
gunners in creating these formulas, as well as to provide important
technical information about early gunpowder manufacturing.

To do this, the researchers identified over 20 gunpowder recipes from
medieval texts dated 1336 to 1449 A.D. They prepared the powders and
measured the energies released just before and during combustion using differential scanning calorimetry and bomb calorimetry. They also tested
a few of the recipes at a West Point firing range using a replica of an
early 15th-century stone-throwing cannon.

In general, in the period 1338-1400 A.D., the percentage of saltpeter
increased and charcoal decreased, causing lower heats of combustion,
which could have produced safer recipes for medieval gunners. After
1400 A.D., the percentage of saltpeter (the most expensive ingredient) decreased slightly, while sulfur and charcoal increased, raising the heat
of combustion, although not as high as for the earliest recipes. Certain additives, such as the combination of camphor and ammonium chloride,
appeared to make gunpowder stronger, whereas others, such as water or
brandy, did not show energetic advantages, but might have served other purposes. For example, they might have made the material more stable
during transport or storage. Although the researchers have characterized
the gunpowders in the lab and in limited experiments on the firing range,
more field work must be done to evaluate which formulation would perform
the best in historical contexts, they say.

========================================================================== Story Source: Materials provided by American_Chemical_Society. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Tessy S. Ritchie, Kathleen E. Riegner, Robert J. Seals, Clifford J.

Rogers, Dawn E. Riegner. Evolution of Medieval Gunpowder:
Thermodynamic and Combustion Analysis. ACS Omega, 2021; 6 (35):
22848 DOI: 10.1021/ acsomega.1c03380 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210922121347.htm

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