| Abstract: | Studies in the epoxidation of natural rubber latices are described. Investigated epoxidation routes include the use of bromohydrin intermediates, hydrogen-peroxide-catalyzed systems, and preformed peracetic acid. The latter reagent allows almost quantitative epoxidation of natural rubber up to high modification levels with no detectable side reactions. Kinetic studies show that the peracetic acid epoxidation is second order in peracid and rubber hydrocarbon with an overall activation energy of 56.2 kJ/mol. Epoxidation leads to a progressive increase in Tg and polymer density with increase in modification level. The effect of modification on solvent swelling and mechanical properties of the DICUP-crosslinked rubbers are reported. |
