Effect of inorganic filler on the crystallization, mechanical properties and rheological behavior of poly(trimethylene terephthalate)

Poly(trimethylene terephthalate) filled with nano-CaCO3 and ultra-fine talc was prepared by melt blending using a co-rotating twin screw extruder. The effect of these two inorganic filler on the crystallization and melting behavior, mechanical properties and rheological behavior of PTT were characterized. The DSC results indicated that both nano-CaCO3 and ultra-fine talc exhibited heterogeneous nucleation effect on the crystallization of PTT, and more significant nucleation effect were observed in PTT/nano-CaCO3 composite due to the smaller size and better dispersion of nano-CaCO3 in PTT matrix. Mechanical properties study suggested that the incorporation of nano-CaCO3 and ultra-fine talc greatly improved the tensile and flexural properties of PTT. Ultra-fine talc tends to lower the impact properties, while nano-CaCO3 tend to increase the impact strength of the PTT/nano-CaCO3 composite. When 2 wt.% of nano-CaCO3 was added, the impact strength increased by one time. Rheological behavior study indicated nano-CaCO3 exhibited plasticization effect on PTT melt and decreased the viscosity of PTT, while ultra-fine talc increased the viscosity of PTT due to the hindrance of the layer structure of talc.