Studies on crystal transition of polyamide 11 nanocomposites by variable-temperature X-ray diffraction

Abstract

Polyamide 11 (PA11) and its nanocomposites with different organoclay loadings were prepared by melt-compounding and subsequent pelletizing. The crystal phase transitions of PA11 and its clay nanocomposites were investigated by variable-temperature X-ray diffraction. It was found that the Brill transition of the nanocomposite was 20 K higher than that of the neat PA11 for both heating and cooling processes. The PA11 d-spacings of the nanocomposites were observed to be smaller than those of the neat PA11 for melt crystallization. The constraints imposed by the addition of layered clay, restricting the thermal expansion of the polymer chains, are probably responsible for such a reduction of the d-spacing.