Annealing-induced high impact toughness of immiscible isotactic polypropylene/poly(acrylonitrile-butadiene-styrene) blend

In present work, acrylonitrile-butadiene-styrene graft copolymer (ABS) with dual roles of macromolecular beta nucleating agent and organic rigid particles was introduced into isotactic polypropylene (iPP) via melt blending, and the iPP/ABS blend samples were further annealed at moderate temperature (120-140 degrees C) for 3 h. The corresponding microstructural evolution of pure iPP and ABS-toughened iPP upon annealing was analyzed with differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM) in detail. The results showed that the introduction of ABS and further annealing treatment have synergistic toughening effect on iPP. For the iPP with the addition of 4 wt% ABS, the impact strength is increased by 77%. After annealing at 130 degrees C for 3 h, the impact strength of iPP alone is 72% higher than that of its unannealed counterpart, while this value is increased remarkably by 258% for the iPP/ABS blend. The remarkably elevated impact toughness of iPP blended with ABS upon annealing could be ascribed to favorable heterogeneous nucleation effect of ABS, promoted mobility of chain segments in the amorphous region of iPP, and enhanced interfacial interaction between the iPP and ABS upon annealing.

Automated summary

This study introduces ABS into iPP and further annealing treatment to improve the impact toughness of iPP. The introduction of ABS and annealing treatment have a synergistic effect on toughening iPP.