Description of the dynamic moduli of poly(trimethylene terephthalate)/polyamide-12 blends in molten state

Binary melt blends of two thermoplastics—poly(trimethylene terephthalate) (PTT) and polyamide-12 (PA12)—having a large difference in zero-shear viscosity values, were prepared in different blending ratios (PTT/PA12 90/10, 75/25, 25/75, 10/90) by means of a twin-screw extruder. Scanning electron microscopy (SEM) confirmed droplet morphology subsequently quantified using image analysis. Dynamic rheological behavior at blending temperature (230°C) was also recorded on a parallel plate oscillatory rheometer within the linear viscoelastic range. The applicability of two emulsion models, the Palierne analysis plus the Gramespacher and Meissner model, as well as a micromechanical model, the Coran analysis, to describe the dynamic moduli of the system in different compositions was investigated and also a comparison on these models was presented. POLYM. ENG. SCI., 45:1401–1407, 2005. © 2005 Society of Plastics Engineers