Compatibility in physical blends of polyethylene/polybutene-1

In this study, two types of low density polyethylene with different branches are melt blended with polybutene-1 homo-polymer (PB-1) and the effect of molecular architecture on the compatibility of the blends are investigated. Physical blends of low density (LDPE) and linear low density polyethylene(LLDPE) with different amounts of 5, 10 and 20 wt.% of polybutene-1were prepared using a co-rotating twin-screw extruder. SEM images demonstrate matrix-droplet morphology for the blends which is the sign of incompatibility. Not only the average particle size of PB-1 in LDPE matrix is smaller than LLDPE matrix, but also the number of droplets is more than LLDPE/PB-1 blends. Hence, LDPE/PB-1 system is more compatible in comparison with LLDPE/PB-1 blend. Moreover, Cole-Cole diagram for LDPE/PB-1 is closer to circular shape showing better homogeneity