Polymer blends constitute a valuable way to produce relatively low cost new materials with properties sometimes exhibiting synergistic effects compared to those of the pure components. LLDPE/LDPE blends are widely used industrially to improve the processability of LLDPE or the elongational properties of LDPE, like melt strength. This improvements are beneficial for extrusion and film blowing processes respectively. One of the still debated open questions concerning the structure of polyethylene blends is the miscibility of the two phases, whose investigation is complicated by the identical chemical structure of the two components [1,2]. Deviations from the log-additivity rule of the newtonian viscosity are often taken as a signature of immiscibility. The reason is that theories for miscible blends, like double reptation, predict for the viscosity trends very close to this simple empirical rule. The aim of this work is to characterize the rheological behavior in shear and elongation of five series of LLDPE/LDPE blends whose parent polymers have been chosen with different viscosity and SCB content and length
Shear and Elongational Melt Rheology of LLDPE/LDPE blends
DOGHIERI, FERRUCCIO
2009
Abstract
Polymer blends constitute a valuable way to produce relatively low cost new materials with properties sometimes exhibiting synergistic effects compared to those of the pure components. LLDPE/LDPE blends are widely used industrially to improve the processability of LLDPE or the elongational properties of LDPE, like melt strength. This improvements are beneficial for extrusion and film blowing processes respectively. One of the still debated open questions concerning the structure of polyethylene blends is the miscibility of the two phases, whose investigation is complicated by the identical chemical structure of the two components [1,2]. Deviations from the log-additivity rule of the newtonian viscosity are often taken as a signature of immiscibility. The reason is that theories for miscible blends, like double reptation, predict for the viscosity trends very close to this simple empirical rule. The aim of this work is to characterize the rheological behavior in shear and elongation of five series of LLDPE/LDPE blends whose parent polymers have been chosen with different viscosity and SCB content and lengthI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
