David Spence (rubber chemistry)

Three years later, he accepted a position as the research lab director at the Diamond Rubber Company in Akron, Ohio.

Vulcanization is the process by which natural rubber is strengthened by cross-linking the different polymer chains, with either elemental sulfur bridges or other molecules known as accelerators.

In 1912, Spence was working with George Oenslager at Diamond Rubber to discover different additives to overcome these shortcomings.

Working off of Oenslager's aniline additives, Spence discovered that p-aminodimethylaniline was a far superior accelerator, requiring only 0.5 weight percent added to the vulcanization process, to vastly improve the tensile strength of the rubber.

Spence patented methodologies to both improve the quality and yield of rubber produced from Guayule via conventional mechanical techniques in 1933.

[8] Upon investigation, Spence determined that the drying of the Guayule was responsible for the high variability in both the yield and quality of the latex.

[8] The retting process improved the milling extraction process of Guayule upwards of six percent, and improved the tensile strength from 1800-2000 psi upwards of 2800 psi, a tensile strength comparable to that of the rubber trees.

[9] To solve the rubber shortage, Spence and scientists from Goodyear, Firestone, Goodrich, and New Jersey Standard, joined together under a patent sharing agreement.

Spence, together with Dr. Alexander Clark, provided a method for producing synthetic isoprene, via the dehydration of 2,3 dimethylbut-1-en-3-ol and other alcohols using glacial acetic acid.

[10] Due to his involvement in the synthesis of the isoprene monomer, Spence was the first recipient of the Charles Goodyear Medal.

[2] While working at Goodyear, Spence altered the processes for vulcanization and the application of colored dyes to rubber.

[11] In addition to redeveloping the vulcanization process, Spence developed a method for applying dyes to raw rubber.