Relaxation properties of polyoxymethylene and ethylene-octene copolymer blend in solid and melt states

Rheological properties of polyoxymethylene (POM) and ethylene-octene copolymer (EOC) in solid and melt states were investigated. Blends were prepared with a twin screw extruder at broad component wt-to-wt ratios (10, 30, 50, 70, 90 wt% of EOC). The morphology as well as calorimetric, rheological, and elastic properties of the blends were studied. The investigation showed that POM/EOC blends were heterogeneous in nature and had a broad phase transition region between 30 and 70 wt% of POM. Because during processing droplet breakup is enhanced for EOC-rich systems, respective blends show "better" morphology with smaller particle sizes. It was, however, observed that rheological and dynamic characteristics (such as storage Eand loss E'' modules as well as shear elastic Gand viscous G'' modules) were highly influenced by intrinsic incompatibility of POM and EOC. Besides, also the crystallization specifics of the investigated blends influenced their Eand . E''