Influence of Carbon‐Black Nanoparticles on Poly(butylene terephthalate) Fractionated Crystallization in Bicomponent Poly(butylene terephthalate)/Poly[ethylene‐co‐(ethyl acrylate)] Blends

Summary: The crystallization of the PBT minor phase in an EEA continuous matrix has been studied by DSC and SEM. When PBT is the minor phase, PBT crystallizes at a lower temperature, as expected, near Tc,f1 = 105 °C. Introducing different CB nanoparticles into the EEA continuous phase at contents increasing from 0.02 to 5 wt.‐% leads to important modifications of the PBT crystallization. A new PBT exotherm appears at Tc,f2 = 144 °C on the addition of CB, becoming really visible at Tc,f3 = 158 °C and finally moving to Tc,n = 185 °C at high content. The areas corresponding to these new peaks were found to increase to the detriment of that of the fractionated crystallization at Tc,f1 = 105 °C. Morphological studies and interfacial tension measurements were made to understand the surprising activity of the CB. Moreover, the substitution of the EEA phase with the less polar LLDPE confirmed the importance of the strong interactions developed by EEA with CB aggregates. Melting and recrystallization DSC curves for the PBT/EEA 60/40 blend. magnified image Melting and recrystallization DSC curves for the PBT/EEA 60/40 blend.