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.
Synergistic effect in network formation of nylon-6(PA6) nanocomposites containing one dimensional(1D) multi-walled carbon nanotubes(CNTs) and two dimensional(2D) layered double hydroxide(LDH) platelets on improving the mechanical properties has been studied. Mechanical tests show that, with incorporation of 1 wt% LDHs and 0.5 wt% CNTs, the tensile modulus, the yield strength as well as the hardness of the ternary composite are greatly improved by about 230%, 128% and 110% respectively, as compared with neat PA6. This is mainly attributed to the unique, strong interactions between the CNTs and the LDHs as well as the jammed network-like structure thus formed between the nanofillers, as confirmed by the morphological observations. As compared with the binary nanocomposites, a much enhanced solid-like behavior in the terminal region of the rheological curves can clearly be observed for the ternary system, which also indicates the formation of a percolating filler network.
Recently,graphene has attracted numerous interests from both fundamental and applied fields due to its excellent mechanical,thermal,electrical conductivity and other novel properties.This review gives an overview of recent progress on hybridization modifications of graphene with carbon nanomaterials.Some example applications of graphene-based nanohybrids in polymer composites,optical and conducting materials,high performance electrolyte materials and as well as other functional materials are summarized and discussed.
