Preparation of natural rubber/carbon black composite by medhanical coagulation of latex

Abstract

Preparation of natural rubber/carbon black composites by mechanical coagulation of latex was carried out by using a high speed internal mixer. The coagulation was successfully obtained from the mixing speed of 2,800 rpm for 3 minutes. After coagulation, the carbon black particles were poorly dispersed in the rubber matrix. Better dispersion was later obtained when the coagulated NR/CB mixtures was mixed with sulfur curing chemical in a two-roll mill. Coagulation of the NR/CB mixtures was found to depend on types and quantities of CB. The CB content in the shear-induced vulcanizate was lower than the feed amount as analyzed by specific gravity. The vulcanizates containing 30 phr of N330 or N550 had the highest mechanical properties such as tensile strength. A comparison between NR/CB vulcanizates from both methods in terms of mechanical properties revealed that the shear-induced vulcanizates had slightly interior mechanical properties than the conventional ones.