Investigating the Effect of Adding Multiwalled Carbon Nanotubes on the Morphological Properties of Polybutylene Terephthalate

The effect of reinforcement with multi-walled carbon nanotubes (MWCNTs) on the crystallization behavior at non-isothermal melting of polybutylene terephthalate (PBT) was studied using a differential scanning calorimetry at the following cooling rates 2, 5, 10, 20 °C/min, after preparing the samples by adding different ratios of MWCNTs to PBT 0.2, 0.4, 0.6, 0.8, 1, 1.2 wt% using extrusion connected to the mixer. In general, the results showed that the addition of carbon nanotubes led to an improvement in the crystallization rate, a higher crystallization initiation temperature and a crystallization peak temperature. With the increase in the content of MWCNTs, the exothermic peaks became wider. On the other hand, the rise in the cooling rate caused a decrease in the temperature of these peaks. Moreover, it was observed from the results that the presence of MWCNTs made crystallization start at an early stage because these CNTs acted as a strong nucleating agent that enhanced the nucleation of PBT when compared to neat PBT. It also gave a large area for crystal growth thus the structure of PBT became more stable. Furthermore, this addition influenced the properties of the polymer because of increasing the amount of crystallization, where the results indicated that the enthalpy of melting increased with the increase in the rate of addition, but this increase reduced with the increase in the cooling rate. These results show the clear interfere of carbon nanotubes in the polymer matrix.