Modification of rubber by iodoform

Abstract

AbstractThe activity of iodoform (CHI3) toward unsaturated rubbers was examined. Special attention was devoted to cis‐1,4‐(poly)isoprene (IR). The thermal decomposition of CHI3 was studied by ion mass spectroscopy, and the obtained data were used for the identification of pyrolysis products of CHI3 vulcanizates by pyrolytic gas chromatography. The kinetics of the chemical crosslinking of rubber were studied with a cure meter. The changes observed in the chemical structure of rubber were explained on the basis of 13CNMR and Fourier transform infrared spectroscopy, differential scanning calorimetry, equilibrium swelling, and chemical microanalysis data. Apart from crosslinking, a simultaneous modification of the rubber macromolecules took place, specifically the cis–trans isomerization of IR. This resulted in a significant increase in the rubber hardness, especially after a postheat treatment accompanied by oxidation. CHI3–IR vulcanizates behaved like thermoplastics because of the presence of a trans‐1,4 phase, as confirmed by dynamic mechanical thermal analysis. The structure of the macromolecules treated with CHI3 and its effect on the physical properties of the material were compared with those of peroxide–IR vulcanizates. The influence of the modification on the surface energy, bacteriostaticity, and mechanical properties of the vulcanizates was examined. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 177–189, 2007