Influence of intercalated montmorillonite/polyethylene glycol binary processing aids on the rheological and mechanical properties of metallocene linear low-density polyethylene

Organomodified Na+-montmorillonite/polyethylene glycol (PEG) processing aids were prepared. Melt compounding was used to prepare nanocomposites of exfoliated montmorillonite platelets dispersing in a metallocene linear low-density polyethylene (mLLDPE) matrix. The extent of intercalation of PEG into montmorillonite layers and clay platelet exfoliation in the mLLDPE matrix was studied by X-ray diffraction. The influence of montmorillonite/PEG binary processing aids on the rheological properties and sharkskin melt fracture of mLLDPE was studied using a capillary rheometer and scanning electron microscope (SEM). The crystallization and melting characters were also studied by differential scanning calorimetry (DSC) and X-ray diffraction. The montmorillonite/PEG binary processing aids could reduce the viscosity of mLLDPE. Meanwhile, the critical apparent shear rate of the onset of sharkskin melt fracture of mLLDPE was increased by adding the aids. Also the nanocomposite prepared with the montmorillonite/PEG processing aids had better mechanical properties than pure mLLDPE. And the crystallinity, crystallization temperature, crystallization rate and melting temperature of mLLDPE/BPA nanocomposites were increased by adding the binary processing aids, and crystallization of mLLDPE became more complete.