An Experimental Study of Morphology and Rheology of Ternary Pglass-PS-LDPE Hybrids
Polymers and High Performance Materials
Ternary blends of low-density polyethylene (LDPE). polystyrene (PS), and a low T. tin-based phosphate glass (Pglass) were prepared at compositions ranging from 0-50 vol% Pglass in which either LDPE or PS was the continuous matrix phase. Differential scanning calorimetry was used to investigate the phase behavior of the pure components. PS-LDPE blends and binary Pglass-polymer hybrids. Interesting steady-shear and transient rheology was observed for the hybrids. In particular, the steady shear viscosity curves for the hybrids of phiP(glass) less than or equal to 30% exhibited unusual, four-region flow behavior, similar to that of liquid crystalline polymers. Two Newtonian plateaus at low (gamma less than or equal to 0.1 s(-1)) and moderate (0.4 less than or equal to gamma less than or equal to s(-1)) shear rates connected by two distinct shear-thinning regimes were apparent. This observed rheology is ascribed to a unique composite morphology of these multi-component systems. Rheological data on the binary Pglass-polymer systems suggest that the presence of the Pglass within both PS and LDPE contributes significantly to this unusual behavior, perhaps because of the interfacial behavior between the phases. Micrographs obtained via scanning electron microscopy reveal preferential placement of the Pglass phase dispersed within the PS-phase and surrounding the LDPE phase. Optical shearing data confirmed the evolution of this microstructure under specific shear conditions.
Polymer Engineering and Science
Guschl, P. C.,
Otaigbe, J. U.
(2003). An Experimental Study of Morphology and Rheology of Ternary Pglass-PS-LDPE Hybrids. Polymer Engineering and Science, 43(6), 1180-1196.
Available at: http://aquila.usm.edu/fac_pubs/3259