Compatibilization of Isotactic Polypropylene (iPP) and High-Density Polyethylene (HDPE) with iPP–PE Multiblock Copolymers

By Jun Xu, J. Eagan, Sung‐Soo Kim, Sanshui Pan, Bongjoon Lee, Kristine Klimovica, Kailong Jin, Ting-Wei Lin, M. Howard, Christopher J. Ellison and 3 more. Macromolecules, 2018

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A series of isotactic polypropylene (iPP) and polyethylene (PE) diblock, tetrablock, and hexablock copolymers (BCPs) were synthesized with tunable molecular weights using a hafnium pyridylamine catalyst. The BCPs were melt blended with 70 wt % high-density PE (HDPE) and 30 wt % iPP commercial homopolymers at concentrations between 0.2 and 5 wt %. The resulting blend morphologies were investigated using TEM, revealing uniformly dispersed iPP droplets ranging progressively in size with increasing BCP content from three-quarters to one-quarter of the diameter of the uncompatibilized mixture. Tensile tests revealed a dramatic enhancement in toughness based on the strain at break which increased from 10% for the unmodified blend to more than 300% with just 0.2 wt % BCP and over 500% with the addition of 0.5 wt % BCP or greater. Incorporation of BCPs in blends also improved the impact toughness, doubling the Izod impact strength to a level comparable to the neat HDPE with just 1 wt % additive. These improved bl...

Subfields: Biomaterials, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/35e91dc18cc6d68b7969922e634d77617db186a5