Nanodiamond (ND)-based polyamide (PA) 66 nanocomposite studied with infrared (IR) microscopy and time-domain nuclear magnetic resonance (TD-NMR) combined with two-trace two-dimensional (2T2D) correlation analysis

Nanodiamond/polyamide (ND/PA) nanocomposite was examined with infrared (IR) microscopy and time-domain nuclear magnetic resonance (TD-NMR) to elucidate in detail the interphase between amino function-alized ND (ND-NH2) and PA 66. An IR image of the ND/PA nanocomposite suggested the uniform nanoscale distribution of the ND-NH2 particles thanks to the spherical shape and accessible external surface of ND terminated with reactive amino groups. On the other hand, a substantial level of change was observed in T2 decay curves when the ND-NH2 particles were incorporated in the PA 66. The fine features of the thermally induced changes in the decay curves were readily analyzed with the two-trace two-dimensional (2T2D) corre-lation method. The variation in the asynchronous correlation intensity indicated that the changes observed in the mechanical properties of the ND/NH2 may be attributed to the development of crosslinking between tie chains in the amorphous region via the interaction between the ND-NH2 and PA 66. Accordingly, such firm links have a substantial effect in preventing the displacement of the amorphous domain, which eventually increases the Young's modulus but reduces the ductility of the PA.

Automated summary

The nanodiamond/polyamide (ND/PA) nanocomposite was investigated using infrared microscopy and time-domain nuclear magnetic resonance (TD-NMR). It was found that ND-NH2 particles were uniformly distributed in the nanocomposite due to their spherical shape and accessible external surface. The incorporation of ND-NH2 particles in PA 66 resulted in substantial changes in the T2 decay curves. The development of cross-linking between ND-NH2 and PA 66 was found to contribute to the changes in the mechanical properties of the nanocomposite.