The compatibility between m-LLDPE and two sorts of HDPE with different molecular weights in the melt state was investigated with rheological methods

nonisothermal and isothermal crystallization dynamics.The rheological measurements suggested that HDPE and m-LLDPE blends were heterogeneous systems at 190℃ based on the relationship of lgG′ and lgω in the low ω region that deviated the linear model.The DSC results showed that with an increase in the content of m-LLDPE

the melting peak of HDPE shifted to lower temperature

suggesting that HDPE and m-LLDPE may be partially compatible.When the blends were cooled from the melt to temperatures where HDPE could crystallize

but the m-LLDPE couldn’t

the Avrami exponent n of high-Mw HDPE increased slightly compared to that of pure HDPE

and the content of m-LLDPE had little effect on the vales of n.Meanwhile

the crystallization half-time (or crystallization rate) of high-Mw HDPE was very similar to that of pure HDPE.However

the Avrami exponent and the crystallization rate of the low-Mw HDPE decreased with an increase in the content of m-LLDPE

indicating that the m-LLDPE retarded crystallization of HDPE

possibly due to the reasons including the dilution of HDPE by m-LLDPE (m-LLDPE as a solvent in molten state)

hindrance of viscous m-LLDPE to the HDPE crystallization front

and decreased supercooling degree because of the compatibility between the m-LLDPE and low-Mw HDPE.This provided further evidence that the compatibility of the low-Mw HDPE with m-LLDPE was better than that with the high-Mw HDPE.