Viscoelastic and thermal properties of unzipped multiwalled carbon nanotubes reinforced polyamide-6 composites

The excellent reinforcing capability of carbon nanofillers along with increasing demand for advanced polymer composites in automobiles, aircraft, and defense sectors motivate the research community to explore detailed mechanical, thermal, and electrical properties of carbon-based polymer nanocomposites for various applications. In this work, 0.1 to 7 parts per hundred ratios (phr) of multiwalled carbon nanotubes (MWCNTs) and unzipped MWCNTs (referred to as graphene oxide nanoribbons (GONRs)) were individually reinforced into polyamide-6 (PA6) matrix by twin-screw extrusion and standard sized specimens were prepared by the injection molding process. The interaction among PA6 and nanofillers were analyzed using Raman and FTIR spectroscopy. The oscillatory rheometry measurement at 0.1 rad/s angular frequency showed a 110.7 % rise in storage modulus and a 12.6 % rise in loss modulus for 0.1 phr GONRs reinforcements. Both the values raised by 100 % and 12.5 %, respectively for similar amounts of MWCNTs reinforcements. The thermo-gravimetric analysis (TGA) indicated the optimum thermal stability at 1 phr of GONRs content compared to the increasing stability with increasing MWCNTs content within PA6. The differential scanning calorimetry (DSC) curves indicated the optimum reinforcing capacity of GONRs at 0.5–3 phr reinforcements, as compared to those increasing for increasing MWCNTs content. An optimum reinforcing capacity at lower amounts of GONRs as compared to MWCNTs was confirmed from shifting trends of intensity peaks in Raman and FTIR spectra curves of the composites. It was attributed to high surface area and functional groups along the edges of GONRs. Altogether, the GONRs/PA6 composites possess excellent potential for applications in automotive and aerospace components, ballistics equipments, electronics, biomedicals, sensors, etc., requiring high mechanical and thermal stability.