Crystallization Behavior of Polyamide 1010-Single-Walled Carbon Nanotube Nanocomposites under High Pressure

The PA1010 (polyamide 1010)-SWCNT (single-walled carbon nanotube) nanocomposites crystallized at different temperatures and pressures for 30 min are prepared by an XKY-61200MN type high-pressure apparatus. The structure, crystallization behavior and morphological feature of high-pressure crystallized samples are studied by XRD (X-ray diffraction), DSC (differential scanning calorimetry), SEM (scanning electron microscope) and TEM (transmission electron microscope). The results show that high-pressure melt crystallization occurs in the pressure range of 1.0-2.5 GPa, while high-pressure annealing occurs in 3.0 and 4.5 GPa. Both melt crystallization and annealing under high pressure contribute to the thickening of polymer lamellar crystals, and moreover, the effect of high pressure melt crystallization is superior to that of high-pressure annealing. XRD results show that the triclinic form of PA1010 remains unchanged after high-pressure treatment, and both melt crystallization and annealing under high pressure can decrease (100) and (010) crystal plane spacing, and namely the high-pressure treatment results in close packing of polymer molecular chains. DSC results show that elevating the pressure and temperature during melt crystallization under high pressure can lead to the formation of crystals with larger lamella thickness, and the highest value of melting point and crystallinity obtained in the sample crystallized at 2.0 GPa and 350 ℃ are 208.5 ℃ and 64.6%, respectively. The large-sized crystals with c axis thickness exceeding 150 m are detected by SEM and TEM in the sample crystallized at high pressure. The interpenetrating network structure between the SWCNT and PA1010 matrix is formed, and the rigid SWCNT as high pressure nucleating agent can promote growth and thickening of PA1010 crystals under high pressure.