Synthesis and characterization of liquid crystalline polyester/graphene and a study of their properties.

A new rod-like thermotropic liquid crystalline polyester (TLCP) material and its nanocomposites based on different concentrations of graphene were synthesized by in-situ high-temperature solution polymerization. The resulting nanocomposites were characterized using XRD, microscopic analysis (POM, SEM, and TEM), spectroscopic analysis (FT-IR, UV-Vis, and fluorescence), and thermal analysis (TGA and DSC). The XRD and POM methods showed that the composite materials exhibited only the nematic phase. The TEM images revealed that the graphene were distributed in the polymer with sizes ranging from 100 to 200 nm. The absorption spectroscopy data showed that the electronic properties of graphene were mostly retained without damaging their two-dimensional electronic properties, together with the analysis of the maximum absorption spectrum and concentration of the composites in terms of the Lambert-Beer law. The fluorescence from the TLCP moiety was almost completely quenched and red shifted by graphene, indicating that the linkage mode facilitated effective energy and electron transfer between the rod-like TLCP and the extended pi-system of graphene. Therefore, this novel nanocomposite material exhibits excellent thermal properties based on the thermogravimetric analysis.

Fabrication of magnetic Ni nanoparticles functionalized water-soluble graphene sheets nanocomposites as sorbent for aromatic compounds removal.

The magnetic Ni nanoparticles functionalized water-soluble graphene sheets nanocomposites (Ni@GSs-C(CH(3))(2)COONa) were fabricated via a facile and mild strategy. We designed a simple and efficient approach (the addition of cyano radicals) to improve the water solubility of nanocomposites. The Ni@GSs-C(CH(3))(2)COONa nanocomposites had great potential as an effective absorbent for removing aromatic compounds from waste water owing to their rapid absorption rate, high absorption capacity, convenient magnetic separation and re-use property.

2, 2'-(Phenylazanediyl) diacetic acid modified Fe3O4@PEI for selective removal of cadmium ions from blood.

A water-dispersible and supermagnetic nanocomposite (PAD-PEG-Fe(3)O(4)@PEI) has been successfully synthesized using polyethylenimine (PEI, Mol MW = 10000) coated supermagnetic Fe(3)O(4)-NH(2) which was modified with 2, 2'-(phenylazanediyl) diacetic acid (PAD) through the bridge of poly(ethylene glycol) (PEG, Mol MW = 2000). The average particle size of PAD-PEG-Fe(3)O(4)@PEI was determined by TEM, and was about 50 nm. From magnetic hysteresis cycles for PAD-PEG-Fe(3)O(4)@PEI at room temperature, the saturation magnetization (Ms) was shown to be 58.14 emu g(-1). Inductively coupled plasma spectrometry (ICP) analysis showed that the designed magnetic nanocomposite can remove 98% and 80% of Cd(2+) from water and blood, respectively.

Properties of thermotropic liquid crystalline polyester nanocomposites derived from multi-walled carbon nanotubes.

A series of nanocomposites containing multi-walled carbon nanotubes (MWNTs) and terephthaloyl-di-p-oxybenzoyl chloride-triethylene glycol copolyester (T-T) were prepared by in-situ high-temperature solution polycondensation. The liquid crystalline properties and thermal stability of the resulted MWNTs/T-T nanocomposites were investigated by wide-angle X-ray diffraction (WAXD), polarized optical microscopy (POM), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA), respectively. The results showed that MWNT doping at a low concentration improved the thermal stability of T-T matrix and expanded the nematic temperature range without largely changing its conformation, making it more suitable for processing. The dispersion of MWNTs and interfacial interactions between the thermotropic liquid crystalline polymer (TLCP) molecules and the carbon nanotubes (CNTs) were investigated by scanning electron microscopy (SEM) and optical spectroscopies. The UV-vis spectroscopy and fluorescence spectra supported a strong pi-pi* interaction between the polymer and the nanotube.

Aryne cycloaddition: highly efficient chemical modification of graphene.

We have developed a simple and efficient approach for the synthesis of chemically converted graphene sheets via aryne cycloaddition under mild reaction conditions. The resulting highly functionalized and thermally stable aryne-modified graphene sheets can be well dispersed in various solvents.