C. Nah et S. Kaang, RHEOLOGICAL AND MECHANICAL-PROPERTIES OF STYRENE-BUTADIENE RUBBER COMPOUNDS CONTAINING RUBBER POWDER VULCANIZATES, Journal of polymer engineering, 17(4), 1997, pp. 323-338
The cure behavior, rheological property, and tensile strength of styre
ne-butadiene rubber (SBR) compounds containing different sizes of rubb
er powder vulcanizates (RPV) were investigated by varying the loading
from 0 to 40 phr. Six different sizes of RPV were selected to see the
effect of particle size. A typical reclaimed rubber powder was also us
ed to see the reclaiming effect. The average particle size of the RPVs
ranged from 70 to 2,000 mu m. In the cure characteristics, as the pow
der loading was increased, the maximum torque, scorch time, and optimu
m cure time decreased, while minimum torque increased. At lower shear
stresses (or shear strains) the viscosity of the rubber compounds incr
eased noticeably with the addition of RPV. This increase was diminishe
d at higher shear stresses. However, the die swell decreased when RPV
was added. With increased powder loading the tensile strength decrease
d dramatically at lower powder concentrations, similar to 10 phr, and
then the rate of this decrease became slower at higher concentrations.
A power-law relation was observed between the tensile strength reduct
ion and the particle size of the RPV.