Effect of Silica Nanoparticle on the Quiescent and the Shear Induced Crystallization Behaviors of Poly(trimethylene terephthalate)

The isothermal crystallization behavior of poly(trimetylene terephthalate) (PTT) containing silica nanoparticles was investigated. The addition of silica nanoparticles increased the crystallization temperature of PTT by 20 °C and notably decreased the size of the crystals. Higher silica nanoparticle content led to greater depression of equilibrium melting temperature. Quiescent isothermal crystallization in DSC capsule showed that silica nanoparticles acted as a nucleating agent for PTT and decreased the half time for crystallization. In the case of PTT containing silica nanoparticles 1 and 2 wt %, however, little difference in the crystallization behavior was noticeable, suggesting that the silica content of 1 wt % is the critical level for nucleating. Isothermal crystallization under dynamic shear showed similar crystallization behavior with quiescent crystallization. In addition, higher shear rate accelerates the crystallization rate of PTT. However, X-Ray diffraction result revealed that the content of silica nanoparticles and application of shear had little effect on the resultant crystal structure.