Effects of Domain Interfaces on the Rheological Properties of Polybutadiene / Polyisoprene Blends
H Jeon, A Nakatani, Charles C. Han, R H. Colby
The viscoelastic properties of a near critical polybutadiene(PB)/polyisoprene(PI) blends were investigated in oscillatory shear above and below the lower critical solution temperature (LCST). The dynamic loss modulus of a near critical PB/PI blend above and below the LCST is well described by means of a log additive mixing rule. A single master curve in the loss modulus of the critical blend exhibiting WLF behavior was obtained below the LCST by using the time temperature superposition (TTS) principle. However, the storage modulus and loss tangent above the LCST deviate from both the TTS principle and the log additive mixing rule. The phase separated PB/PI blends within the linear viscoelastic regime display higher than expected values of storage modulus at low frequencies. This is due to the interfacial tension between the two phases of the blend. In contrast, the loss modulus of the blends at low and high frequencies is not affected by the interfacial tension. We also found a discontinuity in the temperature dependence of the dynamic storage modulus. The discontinuity is related to the phase separation temperature of the blend, and it is affected by oscillatory shear.
, Nakatani, A.
, Han, C.
and Colby, R.
Effects of Domain Interfaces on the Rheological Properties of Polybutadiene / Polyisoprene Blends, Journal of the American Chemical Society
(Accessed June 9, 2023)