Photo-degradation of natural rubber films for natural gas application

Abstract

Natural rubber (NR) can be degraded depending on various factors such as heat, mechanical force, chemical reaction, and light. Light is an attractive factor because it degrades NR under low temperature and pressure. In this research, the photo-degradation of NR films was carried out to investigate the effects of the light, temperature, and catalysts on the reduction of the weight-average molecular weight (Mw) and the double bonds in the NR films. The NR films, with and without catalysts, titanium dioxide (TiO[subscript 2]), and potassium persulfate (K[subscript 2]S[subscript 2]O[subscript 8]), were exposed to light from a mercury light bulb at differenct light densities and temperature. After exposure, the Mw of the NR films was analyzed using the gel permeation chromatography (GPC) method. The reduction of Mw was studied, and the Mw distribution information from the GPC was used to calculate the number of double bonds in the NR films. A kinetic model for the 1[superscript st] order reaction with random scission has been applied to this photo-degradation process. Some other physical properties of the NR films were also investigated. From this fundamental knowledge obtained, NR can probably be developed for a containment of methane hydrate, or for adsorption of gaseous fuels.