High performance PEEK/carbon nanotube composites compatibilized with polysulfones-II. Mechanical and electrical properties

Influence of carbon nanotubes on the thermal, electrical and mechanical properties of poly(ether ether ketone)/glass fiber laminates

“…It appears that the disadvantages of the compatibilization with respect to SWCNT conductivity are outweighed by the enhanced dispersion and adhesion attained in the presence of the polysulfone; overall, the electrical conductivity attained in the laminates reinforced with wrapped SWCNTs is on average one order of magnitude higher than that obtained for the non-compatibilized samples. This is in contrast with the results obtained from the previous study of PEEK/SWCNT composites [28], where the incorporation of the compatibilizer maintained the level of conductivity of the samples. The discrepancy could be attributed to the influence of additional factors, such as the presence of nanoscale pores.…”

“…The aforementioned effect has been previously reported for PEEK/CNF composites [24] and was attributed to a more inhomogeneous amorphous phase in the composites in relation to the pure matrix. It is worthy to note that the trends observed from the DMA spectra of the different laminates are consistent with those described previously for PEEK/SWCNT and PEEK/SWCNT + PEES composites [28], where the compatibilized samples, in particular those including laser-grown CNTs, exhibited the highest E 0 and T g values. These results Table 3 -Storage modulus E 0 at 25, 100 and 200°C, glass transition temperature T g , tan d maximum value and width at half maximum b for the different PEEK laminates, obtained from dynamic mechanical analysis measurements at a frequency of 1 Hz.…”

“…This indicates that the incorporation of the polysulfone reduces stress concentrations at the polymer-nanotube interface, thereby improving the matrix ductility. Similar trends were observed from the previous comparative study of PEEK/SWCNT composites with and without compatibilizer [28], thereby confirming the effective role of the polysulfone. The drawing process should be considerably more limited in composites including non-wrapped SWCNTs due to the presence of small CNT agglomerates, which strongly restrict plastic deformation of the matrix.…”

“…Composites with good thermal conductivity have a great number of potential applications such as printed circuit boards, connectors, thermal interface materials, heat sinks, etc. The thermal conductivity (k) of neat PEEK resin is $0.23 W m À1 K À1 [28], and that of glass fiber fabric around 0.05 W m À1 K À1 [36]. Phonon transport in these composites is in the form of diffusion, and since CNTs exhibit ballistic transport properties [37], the dispersion of CNTs into the matrix will significantly enhance phonon diffusion, thereby improving thermal conductivity.…”

“…Recently, our group has demonstrated that the properties of this high-performance material can be significantly enhanced by the addition of single-walled carbon nanotubes (SWCNTs) [25,26]. In particular, the addition of small amounts of SWCNTs wrapped in compatibilizing agents such as polysulfone, an amorphous thermoplastic miscible with and structurally similar to PEEK, leads to a remarkable increase in the storage and Young's modulus, T g and degradation temperatures of the matrix [27,28]. Polysulfone possesses dual affinity with PEEK and the SWCNTs; its phenyl moieties interact with the matrix through p-p stacking as well as with the sp 2 -bonded hexagonal networks of the nanofillers.…”