Effect of silicon carbide nanoparticles on the morphology, rheological properties, and mechanical performance of polyamide 6/nitrile butadiene rubber nanocomposites

In this work, the morphology, crystallization behavior, viscoelastic properties, and mechanical performance of polyamide 6/acrylonitrile-butadiene rubber/silicon carbide (PA6/NBR/SiC) thermoplastic elastomer (TPE) nanocomposites were investigated. These materials were prepared by melt mixing PA6/NBR at weight ratios of 80/20 and 60/40, with SiC nanoparticle loadings from 0 to 7 wt% to study the role of nanoparticle incorporation and content on morphology, crystallization behavior, viscoelastic response, and mechanical performance. Scanning electron microscopy (SEM) revealed a sea-island morphology with NBR dispersed as droplets in the PA6 matrix. SiC nanoparticles reduced the droplet size, from 471 nm for P80N20S5 sample to 847 nm for P60N40S5 sample, while transmission electron microscopy (TEM) showed that SiC nanoparticles reduced the domain size and were selectively localized in the PA6 phase. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results showed that while SiC nanoparticles promoted earlier crystallization, they limited lamellar growth and crystal perfection. Rheological and dynamic mechanical thermal analysis (DMTA) measurements demonstrated increased modulus values and reduced damping with increasing nanoparticle content, indicating enhanced elastic response and restricted chain mobility. Tensile properties improved up to an optimum loading (5 wt%), followed by a slight decline at higher contents. At this loading, tensile strength increased from 11.99 to 17.82 MPa for P60N40 samples and from 22.10 to 29.31 MPa for P80N20 samples. Accordingly, this paper can provide an insight into structure-property relationships in ternary TPEs containing nanoparticles and identify limits for achieving balanced performance.