Interfacial phase of nylon 6 strongly adsorbed on alumina particles

The interfacial phase structures of nylon 6 with alumina nanoparticles were investigated by X-ray diffraction measurements, infrared spectroscopy, and differential scanning calorimetry for composites with high weight fractions (30-70%) of alumina. The melting and crystallization temperatures were decreased by the addition of alumina nanoparticles. Changes in the infrared spectra of the composites suggested that the alumina nanoparticles strengthened the hydrogen bonds of nylon 6 at their interfaces. The composites were dispersed in formic acid, which is a good solvent of nylon 6, and the precipitates were collected by centrifugation. The infrared spectrum and the results of thermal gravimetric analysis suggested the presence of nylon 6 in the precipitate even after washing with formic acid. These results indicate the existence of an interfacial phase where nylon 6 is strongly adsorbed onto alumina nanoparticles, and its crystallization behavior and structure formed by the hydrogen bonds were affected by the interfacial interaction. Composites of nylon 6 and large amounts of alumina nanoparticles were prepared to investigate nylon 6 at its interface with alumina. DSC curves obtained by heating and cooling the slowly cooled samples indicate decreases in melting and crystallization temperatures. The melting enthalpy and XRD patterns show a decrease in the degree of crystallization with the addition of alumina. The IR spectra suggest that hydrogen bonds were enhanced at the interface.