Crystallization and morphology of polyamide 1010/single-walled carbon nanotube nanocomposites under elevated pressure

Polyamide 1010/single-walled carbon nanotube (PA1010/SWNT) nanocomposites prepared by melt compounding were treated under a pressure of 2.0 GPa and at three different temperatures (250, 300 and 350 degrees C) for 30 min. Then, all the samples were naturally cooled to room temperature from the melt prior to release of the applied pressure. The melting temperature and crystallinity of high pressure crystallized samples were shifted to a high value after the treatment temperatures under pressure. The infrared spectrum of the high pressure crystallized samples showed a considerable improvement of crystalline order, a closer packing of the polymer chains due to the shorter N?C bond length, and the presence of a large proportion of free N?H groups resulting from antiparallel chains in flat zigzag conformation. Wide-angle X-ray diffraction measurements indicated that the high pressure gave rise to an increase in crystallite dimensions as well as to a decrease of the distance between the crystal planes bonded by the hydrogen bond (100) planes and by the van der Waals force (010) planes. Scanning electron microscope images showed that denser texture, thicker covering layers on the tubes and regular cubic sugar-like crystals with a lateral length of about 1.5 mu m could be detected on the fracture surface of PA1010/SWNT nanocomposites crystallized under pressure. Copyright (c) 2012 Society of Chemical Industr