RHEOLOGICAL BEHAVIOR OF LLDPE LDPE BLENDS UNDER ELONGATIONAL DEFORMATION - THE EFFECT OF MOLECULAR-STRUCTURE AND MELT MORPHOLOGY/

Blends made of one linear low density polyethylene (LLDPE) and either of two low density polyethylenes (LDPE 1 and LDPE 2) were rested in el ongational modes of deformation using elongational viscosity and melt strength test. In addition to rheological measurements the melt miscib ility of the blends was ascertained by the differential scanning calor imetry (DSC) test on melt quenched samples. From the results, the rela tion between melt morphology of the blends and their performance under elongation, as well as the influence of molecular structure in partic ular long chain branching, on elongational response were determined. I t was observed that high resistance to elongational deformation of the blends is linked to the immiscibility of the blend components in the melt. On the other hand the influence of long chain branching is to in crease elongational viscosity for the parent polymers, as well as prom oting the blend immiscibility and therefore altering elongational perf ormance of the blends.