Effect of Carbon Nanotubes on the Mechanical, Crystallization, Electrical and Thermal Conductivity Properties of CNT/CCF/PEKK Composites

Carbon nanotube/continuous carbon fiber–reinforced poly(etherketoneketone) (CNT/CCF/PEKK) prepreg tapes were prepared by the wet powder impregnation method, and then the prepreg tapes were molded into laminates. The effects of carbon nanotubes on the mechanical properties, conductivity, thermal conductivity and crystallinity of the composites were studied by universal testing machine, thermal conductivity and resistivity tester, dynamic mechanical analyzer (DMA) and differential scanning calorimeter (DSC). The results show that when the content of carbon nanotubes is 0.5 wt% (relative to the mass of PEKK resin, the same below), the flexural strength and interlaminar shear strength of the laminates reach the maximum, which are increased by 15.99% and 18.16%, respectively, compared with the laminates without carbon nanotubes. The results of conductivity and thermal conductivity show that the higher the content of carbon nanotubes, the better the conductivity and thermal conductivity of the material. DSC results show that the addition of CNT promoted the crystallization of PEKK in the material and decreased the cold crystallization of PEKK. DMA results show that the deformation resistance of the material can be improved by adding an appropriate amount of CNT and the bonding between CF and PEKK can be enhanced, while excessive CNT destroys this phenomenon

Crystallization, rheological behavior and mechanical properties of carbon nanotube/metallocene polypropylene composites

In this paper, metallocene polypropylene (mPP) composites filled with carbon nanotubes (CNTs) were prepared using twin-screw extruder. The crystallization behavior, mechanical properties and rheological behavior were characterized by a differential scanning calorimetry (DSC), universal material testing machine and rotational rheometer. The results of DSC indicated that the effect of CNTs on heterogeneous nucleation of mPP was very obvious and the crystallizability of the resin matrix was improved after adding CNTs, especially the initial crystallization temperature ( T _0 ), crystallization temperature ( T _c ) increased by 9.63 °C and 8.28 °C when the CNTs content was 1.25 wt%. The yield stress and elastic modulus increased to 33.98 MPa and 1605.6 MPa as the CNTs concentration increased to 1.0 wt% in contrast to that of the neat mPP. The results of SEM images showed that the better dispersion and adhesion of CNTs into polymer matrix. The results of rotational rheometer proved that interactions increased between CNTs and mPP as the content of CNTs increasing