FRACTIONATED CRYSTALLIZATION OF HDPE IN PS/POE/HDPE/SBS BLENDS

The fractionated crystallization behavior of the minor dispersed HDPE phase in PS/POE/HDPE/SBS quaternary blends was investigated by differential scanning calorimetry (DSC). Interestingly, we found that the fractionated crystallization behavior of HDPE was molecular weight dependent. At a fixed composition, HDPE with lower molecular weight showed more obvious fractionated crystallization behavior than HDPE with higher molecular weight. This was ascribed to a finer dispersion of HDPE with lower molecular weight, as evidenced by SEM observations. The fractionated crystallization behavior of HDPE in the blends became less obvious with increasing of its content, due to a change of phase morphology from droplet to co-continuous structure. Correspondingly, a change of tensile toughness of the blends from brittle to ductile mode was observed.