Effect of sodium lignosulfonate/nano calcium carbonate composite filler on properties of isotactic polypropylene

A novel composite filler sodium lignosulfonate/nano calcium carbonate (SL/CaCO3) was prepared by dry ball milling. Thermogravimetric analysis revealed that the composite filler SL/CaCO3 had improved thermal properties. The crystallization and melting behavior of isotactic polypropylene (iPP) modified by the composite filler was studied by differential scanning calorimetry. The best complex ratio (1:3) and optimal addition amount (2 wt%) of iPP nucleated by SL/CaCO3 were confirmed. The results reflected that a small amount of SL/CaCO3 into iPP could improve the nucleation ability, and excellent mechanical properties were obtained. The relative contents of β‐crystals (Kβ) in iPP were above 0.83 after addition of the composite filler. At the same time, nano CaCO3 played a significant role in crystallizing the iPP nucleated and greatly influenced the content of β-crystals. The elongation at break was increased by 32.27% and the impact strength was increased by 62.38% compared to those of pure iPP.