The rheometric, mechanical, and dynamic mechanical properties as well as fracture surfaces of natural rubber-mica and polybutadiene rubber-mica vulcanizates were studied. Mica was used in the range of 0-30 phr and the rheometric study was carried out at 160degreesC. The results indicate that the mechanical properties are improved as filler addition increases. Dynamic mechanical testing was used to analyze the observed mechanical behavior. The two elastomers showed different fracture behaviors. (C) 2003 Wiley Periodicals, Inc.