Coupling effects of toughening modification and solid die-drawing process on the morphology and mechanical properties of PP/TMB-5 composites with POE

A traditional strategy for toughening modification of polypropylene (PP) is to utilize the excellent impact resistance of β-PP by introducing β-phase nucleating agent (β-NA) into PP matrix. In this work, highly oriented PP/TMB-5 composites and PP/POE/TMB-5 composites were prepared via solid die-drawing (SDD) at 135 °C. The results show that after SDD, on the existence of β-α phase transformation in processing, the toughness of PP/TMB-5 composites was though improved but still limited. Then, introduced polyolefin elastomer (POE) particles into PP/TMB-5 matrix, β-α phase transformation was suppressed, and the toughness were further improved. The effect of grain refinement caused by β-NA were further enhanced by drawing stress and meantime abundant microsized voids generated between oriented lamellae, which were all beneficial to its toughness. The oriented structure inherently strengthened materials rigidity. Thus, the tensile strength and impact strength of PP/POE/TMB-5 composites after SDD were 145.45 MPa and 30.6 kJ/m², 4.8 times and 3.8 times higher than pure PP, respectively.