Blends of Linear and Short Branched Polyethylenes

Datta and Birley (61) first reported on the crystallization behavior of HDPE/LLDPE blends using DSC and wide-angle X-ray diffraction (WAXD). In the DSC measurements, the blends revealed only one endothermic peak for both fast and slow cooling conditions, indicating that the blend components were cocrystallized. The X-ray 

The effect of branch distribution of LLDPE on the crystallization of HDPE/ LLDPE blends has also been investigated. The DSC and scanning electron microscopy (SEM) studies of Lee et al. (68) found that aZiegler-Natta-catalyzed LLDPE-B having a relatively heterogeneous branch distribution (179,000 Mw, 4.2 PDl, and 16 ethyl branches per 1000 backbone carbons) cocrystallizes with HDPE (147,000 Mw and 3.7 PDl) in a wide range of blend compositions, and at the same time. 

From the results discussed above, it is concluded that the crystallization behavior of HDPE/LLDPE blends depends on the number, length, and distribution of branches in the LLDPE component. In general, it was found that increases in the number and degree of branch distribution in the LLDPE component reduce the tendency of cocrystallization in the LLDPE blend with HDPE. 

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