Effect of β-nucleating agent on crystallization of wollastonite-filled recycled polypropylene composites

The crystallization behavior, melting characteristics, and semicrystalline morphologies of wollastonite-filled recycled polypropylene (R-PP) composites without and with β-nucleating agent were investigated in this study. The crystallization temperature (Tc) of 20 mass% wollastonite-filled R-PP composite is 0.4 °C higher than that of R-PP, suggesting that the adding of wollastonite has little nucleation effect on crystallization of R-PP. However, 0.3 mass% TMB-5 significantly increases the Tc of R-PP and induces a large number of β-crystals in wollastonite-filled R-PP composites. For calcium pimelate-supported wollastonite (β-W) filled R-PP composites, the Tc and the relative β-phase content of R-PP increase with increasing addition amount of β-W (from 1 to 20 mass%). As a result, wollastonite-filled R-PP composites with β-phase content higher than 85% can be obtained by adding 0.3 mass% TMB-5 or 20 mass% β-W, which provides an effective method for realizing high value-added and low-cost recycling of R-PP.