Effect of inorganic fillers in binary processing aids on the rheology of a metallocene linear low‐density polyethylene

Inorganic fillers including porous diatomite, flaky talc, and spherical calcium carbonate were blended with polyethylene glycol (PEG) to prepare binary processing aids, and the effect of varied binary processing aids on the melt flow properties and extrudates distortion of a metallocene linear low-density polyethylene (mLLDPE) was studied. It was found that the binary processing aids exhibit better effect on viscosity reduction of mLLDPE than that obtained when PEG was added alone. The morphology of inorganic fillers influences the effect of binary processing aids. The diatomite/PEG binary processing aid shows the most noticeable effect, followed by the talc/PEG binary processing aid, and then the calcium carbonate/PEG binary processing aid. The influence of particle size of the diatomite on the effectiveness of the diatomite/PEG binary processing aid was also studied. The mechanism for the improved effect of binary processing aids on reducing viscosity of mLLDPE was proposed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1824–1829;2005