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

A novel composite filler sodium lignosulfonate/nano calcium carbonate (SL/CaCO 3 ) was prepared by dry ball milling. Thermogravimetric analysis revealed that the composite filler SL/CaCO 3 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/CaCO 3 were confirmed. The results reflected that a small amount of SL/CaCO 3 into iPP could improve the nucleation ability, and excellent mechanical properties were obtained. The relative contents of β ‐crystals ( K β ) in iPP were above 0.83 after addition of the composite filler. At the same time, nano CaCO 3 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.