Technical Paper Archive


This site contains all papers presented at Rubber Division, ACS Technical Meetings from 2000-2018. Meetings prior to 2000 are incomplete and papers are added as they are digitized.


For older papers not listed here, please send your request, including Meeting Year, Title, Author, and Paper # to: cbrady@rubber.org


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The Future of Sulfur in the Rubber Industry

Hoover future of sulfur slides

Event: 200th Technical Meeting - Fall 2021
Location: Pittsburgh, PA
Date: October 05, 2021
Author: Fred Ignatz-Hoover
Paper Number: A01

Price: $20.00

  • SLIDES ONLY
    Sulfur has played a critical role in the tire and rubber goods industries. There are 30 well characterized allotropes of sulfur. An allotrope is defined as a material in a solid phase which differs by its crystal structure from other allotropes of the same element. Orthorhombic cyclo-octasulfur, otherwise referred to as “rhombic” sulfur, exists in three crystalline forms. Cyclo-octasulfur is the most thermodynamically stable form of molecular sulfur. In the 1920’s high purity polymeric (insoluble) sulfur was discovered to greatly improve the strength and durability of tires. Since that time, polymeric sulfur has been the sulfur of choice for high strength and durability especially for critical components in tires. Over time, the thermal stability of polymeric sulfur has only narrowly improved. As such formulations and processability of insoluble sulfur containing compounds have practical limitations. Cyclo-dodecasulfur, S12, offers the potential to virtually remove these practical limitations. S12 is the highest melting known allotrope of sulfur, which surprisingly, offers vulcanization kinetics identical to rhombic or polymeric sulfur. The high thermal stability and crystallinity promise to make S12 “The future of sulfur in the rubber industry!”

    Papers from 200th Technical Meeting - Fall 2021

    Items from 200th Technical Meeting - Fall 2021