Effect of β-nucleating agent on crystallization of post-consumer polypropylene

Highlights: • Effect of β-nucleating agent on crystallization of post-consumer PP is studied. • Post-consumer PP with relative β-phase content higher than 0.80 is able to prepare. • It is possible to apply polymorphic modification in post-consumer PP recycling. -- Abstract: The effect of two kinds of β-nucleating agents, an aryl amide derivative β-nucleating agent (TMB-5) and a rare earth complex (WBG), on crystallization of post-consumer polypropylene (PCW-PP) were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (XRD) and polarized-light optical microscopy (POM). The results indicate that introduction of TMB-5 and WBG is able to increase the crystallization temperature of PCW-PP and to induce a large amount of β-crystals. TMB-5 has stronger β-nucleating effect than WBG at low content, while the β-nucleating effect of WBG exceeds that of TMB-5 at a content of about 0.7 wt%, referring to the calculated relative content of β-phase and the concentration of nuclei in PCW-PP. Through adding 0.3 wt% TMB-5 or 0.7 wt% WBG, PCW-PP with β-phase content higher than 0.80 can be prepared, which provides a promising method to realize high-value added recycling of PCW-PP.