The Propellant and Burning Method

Notes re: high explosives and propellants. October 2, 1942.

We’ve discussed in the past the story of how the National Defense Research Committee was created by President Franklin Roosevelt in the summer of 1940, how Pauling joined in September of that year, and how he was assigned to work on hyper-velocity guns along with a group of other scientists. The committee Pauling belonged to was specifically charged with creating a high-performance propellant to use in hyper-velocity guns, and came up with experimental methods for studying powder combustion.

In 1943 Pauling began investigating a powder that resisted the destabilization to which contemporary powders were prone. He discovered that dinitrodiphenylamine was a more effective stabilizer than any other product used at the time. Pauling’s research team engineered several new powders, and his discovery led to a universal changeover from diphenylamine to dinitrodiphenylamine as the new compound was far safer to work with in industrial settings.

Adding to our previous writings on this subject, today’s post will focus specifically on the process of patenting Pauling’s “Propellant, and Method of Controlling the Burning Thereof,” filed June 18, 1945.

Because the research that Pauling and his team were conducting was directly related to the war, a secrecy order was issued by the Commissioner of Patents on Pauling’s application. As a result, certain documents related to the invention appear to have been either embargoed or destroyed, and some information on the subject has been lost.

Pauling’s NDRC authorization papers permitting work on explosives in warfare. May 1, 1944.

I patented, during the war, a class of composite explosives – propellants. And it may be that they are used, to some extent, now. I never got any royalties from that, because the government had an irrevocable royalty-free license, and nobody else was interested in the powder for propelling bazookas and things like that.

So said Linus Pauling in an August 1991 interview with Thomas Hager, author of the Pauling biography, Force of Nature. However, documents held in the Pauling Papers indicate some discrepancy from Pauling’s recollections.  On May 15, 1945, Pauling wrote a statement in which he agreed to assign to the California Institute Research Foundation his entire right, title and interest in the “Propellant and Method of Controlling the Burning Thereof,” OEMsr 881 Pat 1, along with any patent which the Foundation might file, as long as Pauling received a quarterly payment of 15% of the income from the invention. However, as Pauling stated in his interview with Hager, he never received royalties from his propellant invention, so either the California Institute Research Foundation never patented Pauling’s invention, or there was never any income.

Pauling’s patent attorneys, Lyon and Lyon, wrote a letter to the Commissioner of Patents in November of 1948 “in response to the Office Action of June 8, 1948,” in order to amend a patent application, and included a “remarks” section in which they listed all of the unique aspects of Pauling’s rocket propellant. According to them, “The only reference [in Pauling’s amendment] which is directed to a rocket or rocket propellant, is the British reference Piestrak.” (Piestrak was a scientist.) Lyon and Lyon continued, “It is inherently impossible for the propellant shown in this reference to function in the manner of applicant’s propellant…” In other words, Pauling’s propellant was different enough to where it would be impossible for Piestrak’s invention to replicate it.

Lyon and Lyon went on to list all of the different ways in which Pauling’s propellant was unique. According to them, only if the propellant shown by Piestrak were “arranged to burn from one end only and the central or (33) was filled with a propellant” and if the “slow burning cylindrical layers (34) were changed to fast burning cylindrical layers,” then the Piestrak propellant would be similar to Pauling’s. Further, in Piestrak’s invention, one cylindrical portion of the propellant would burn completely before the next one in order to create “spaced impulses,” while in Pauling’s, the portions were all fast-burning.

Next, they compared Pauling’s invention to an that patented by an individual named Maxim. Maxim’s invention “consists in providing in an explosive colloid, throughout its structure, uniformly arranged cells. These cells are shown in his preferred form as being voids.” The voids could also be filled with a fast burning powder, in order to expand the flame rapidly to the walls of the cells. However, Maxim’s methods did not apply to Pauling’s invention because Pauling’s product would be utilized in the confined space of a high-velocity gun.

The Maxim patent was issued in 1896, and was not meant for use in the same conditions as Pauling’s. Furthermore, Maxim’s powder could only function like Pauling’s on occasion and seemingly by accident. Likewise, Maxim’s black powder would not burn at the same rate as Pauling’s product, according to the attorneys.

Lyon and Lyon finished their letter to the Commissioner of Patents requesting favorable reconsideration of the application, which indicates that, in 1948, Pauling was still working on obtaining a patent for his rocket propellant.

Memo from Pauling to Lyon & Lyon, March 22, 1951.

Some three years later, on March 22, 1951, Pauling wrote a memo to Lyon and Lyon titled “Patent application on explosives.” In it, he compared his product to other inventions. According to Pauling, “In our case we are interested in controlling the burning rate – in conferring upon the major propellant material a burning rate other than that characteristic of it.” Pauling added that he was interested in controlling the burning rate by controlling strands, or by other special methods of manufacture of the propellant. He mentioned that another researcher named De Ganahl was not able to control the burning rate of his own propellant.

On March 7, 1952, Pauling received a letter from J.P. Youtz, business manager of the California Institute Research Foundation, informing him that the application serial no. 600,043, (Pauling’s rocket propellants patent) which had been pending in the Patent Office, had finally been rejected by the Examiner “in spite of the fact that there is more evidence to indicate your invention is patentable over the references cited.” April 12 was the deadline for an appeal.

From there, it is unclear as to whether or not Pauling’s claim to a unique rocket propellant and method of burning were ever acted upon. It is possible that the process was patented by Pauling and then passed on to the California Institute Research Foundation or the government. It is also possible that it was passed along to one of these entities and patented later. Or maybe it was not patented at all, and Pauling’s statement in 1991 was the result of a long, complicated legal process carried out during wartime and clouded by secrecy.

In any case, Pauling’s new method of creating rocket propellants and controlling their burning, and particularly his discovery of the stabilizing effects of dinitrodiphenylamine, resulted in an important contribution to safer working practices in the explosives manufacturing industry.