Studies on the Interfacial Effect between Nano-SiO2 and Nylon 6 in Nylon 6/SiO2 Nanocomposites

Low nano-SiO2 loaded nylon 6 (PA6) nanocomposites were readily produced via in situ polymerization. The effect of surface-modified functional groups of nano-SiO2 on the interfacial structure and properties of nylon 6/SiO2 nanocomposites were studied, which indicated that the surfaces of the two kinds of nano-SiO2, namely RNS-A and DNS-3, contained amino groups and alkyl chains, respectively. Furthermore, as-prepared nanocomposites were characterized by means of transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that the PA6 chains were attached to the surface of nano-SiO2 by the modes of physical adsorption and chemical bonding. Nano-SiO2 was found to uniformly disperse inside nanocomposites with RNS-A and DNS-3, thereby increasing the superior strength and toughness of nanocomposites in comparison to the pure PA6. Of particular interest was the enhancement of the thermal stability of nanocomposites by adding RNS-A; meanwhile, DNS-3 had little effect on thermal stability. This was the possibly explained by the enhancement of thermal stability owing to the cross-linked reaction. Moreover, the reaction system exhibited gelatine following the addition of RNS-A up to 1.5wt%.