EFFECT OF VINYL CONTENT ON THE VISCOELASTIC PROPERTIES OF POLYBUTADIENES AND POLYISOPRENES - MONOMERIC FRICTION COEFFICIENT

The rheological behavior of a series of polybutadienes and polyisopren es presenting various microstructures has been characterized over a wi de range of temperatures. The polybutadienes vary in microstructure fr om 11% to 84% vinyl content. The viscoelastic coefficients resulting f rom the time-temperature superposition principle were determined. The Rouse theory modified for undiluted polymers was used to calculate the monomeric friction coefficient, zeta(0), from the transition zone. We determined that the WLF coefficients are the same, and that zeta(0) i s a unique function of (T -T-g) independently of chain microstructure. (C) 1998 Elsevier Science Ltd. All rights reserved.