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 beta-nucleating agent were investigated in this study. The crystallization temperature (T-c) of 20 mass% wollastonite-filled R-PP composite is 0.4 degrees 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 theT(c)of R-PP and induces a large number of beta-crystals in wollastonite-filled R-PP composites. For calcium pimelate-supported wollastonite (beta-W) filled R-PP composites, theT(c)and the relative beta-phase content of R-PP increase with increasing addition amount of beta-W (from 1 to 20 mass%). As a result, wollastonite-filled R-PP composites with beta-phase content higher than 85% can be obtained by adding 0.3 mass% TMB-5 or 20 mass% beta-W, which provides an effective method for realizing high value-added and low-cost recycling of R-PP.