Correlation between S–S bond energy and macroscopic properties in inverse vulcanized polymers

For a series of polymers obtained by the reaction of d -limonene with various amounts of cyclooctasulfur, the enthalpies of formation and combustion were determined using combustion calorimetry. Furthermore, the average values of the S–S bond energies constituting the oligosulfide bridges were calculated. An exponential decrease in the average S–S bond energy was observed until a minimum value was reached with an increase in the number of sulfur atoms forming the oligosulfide sequences. It has been shown that, in certain cases, the thermal, electrochemical, and physico-mechanical properties of inverse vulcanization products vary systematically with changes in the length of the oligosulfide bridges and, consequently, in the average S–S bond energies. A qualitative correlation is proposed between the distribution of relative signal intensities by m / z value in the LDI mass spectra of the synthesized polymers and the S 8 /(unsaturated monomer) ratio employed in the inverse vulcanization reaction.