Rheological behavior of polymer blends

Abstract

SynopsisSteady and oscillatory shearing flow properties of compatible and incompatible polymer blend systems were measured, using a cone-and-plate rheometer. The compatible blend systems investigated are blends of two low-density polyethylenes (LDPE) having different values of molecular weight and blends of poly(methy1 methacrylate) (PMMA) with poly(viny1idene fluoride) (PVDF). The incompatible blend system investigated is a blend of poly(methy1 methacrylate) (PMMA) with polystyrene (PS). It was found that (1) plots of first normal stress difference (711 -722) vs. shear stress (712) and plots of storage modulus (G') vs. loss modulus (G") for the LDPE blends become independent of temperature and blend composition; (2) plots of 711 -7 2 2 vs. 712, and G' vs. G " for the PMMA/PVDF blends become independent of temperature but dependent upon blend composition. It was found further that, for the incompatible PMMA/PS blends, the dependence of 711 -722 on blend composition, when plotted against 712, is different from the dependence of G' on blend composition, when plotted against G". However, in both compatible and incompatible blend systems, plots of 711 -7 2 2 vs. 712 and plots of G' versus G" are independent of temperature. The seemingly complicated composition-dependent rheological behavior of the incompatible blend system is explained with the aid of photomicrographs describing the state of dispersion.

Miscibility of poly(vinylidene fluoride) and poly(methyl methacrylate-co-zinc polyacrylate) ionomers

“…14 (T g was measured at the inflection point of the tan 8 vs. temperature curves). These data deviate from theoretical predictions based on additivity rules, in agreement with the study of PVDF/PMMA blends by Chuang and Han [25]. As a rule, there is much discrepancy between the values reported in the scientific literature for T g of PVDF/PMMA blends [12,15,24,[26][27][28], more likely in relation to the non-standard experimental conditions used for the samples preparation [15].…”

Viscoelasticity and flow behavior of irradiation grafted nano-inorganic particle filled polypropylene composites in the melt state

“…2) in which the same values of the shift factor a T < 2:0 were used for both G 0 (v ) and G 00 (v ). Another test for self-consistency of the raw data provides the G 0 (v ) vs. G 00 (v ) plots [14]. The excellent linearity of this plot (Fig.…”

Morphology and permeability in extruded polypropylene/ethylene vinyl‐alcohol copolymer blends

“…A PMMA/PS blend system was mixed, by Chuang and Han [25], using a twin-screw compounding machine. Subsequently, samples 37 were compression molded into disks for rheological investigations with a cone-and-plate rheometer.…”