Effect of Modification on the Physicochemical and ThermalProperties of Organophilic Clay Modified with Octadecylamine
Organophilic clay was modified by ion exchange reactions using Octadecylamine. The reaction process was carried out at a temperature of 70oC for 90 minutes reaction time in a batch reactor equipped with a mechanical stirrer rotating at a speed of 300 rpm. Physicochemical and thermal 
properties of the clay before and after modification were determined and compared using Field Emission Scanning Electron Microscope/ Energy Dispersive X-ray spectroscopy (FESEM/EDX),Fourier transform infrared spectroscopy (FT-IR) and Thermogravimetric Analyzer (TGA). FESEM images show clearly the micro structural differences between the modified and unmodified clay while EDX shows a compositional changes between modified and unmodified 
clay with the presence of 7.27% carbon in the modified clay. The analysis of FT-IR spectra shows the attachment of some functional groups which are mostly alkyl and hallo-alkyl groups. This is an indication of proper modification. TGA plots of both pure unmodified and organically modified clay attained stability at a temperature between 500oC and 900oC after reduction in weight due to evaporation of moisture and decomposition of the adhered Alkylammonium salts between 30oC and 500oC. This confirmed that thermal stability of the organically modified clay compared favorably with pure natural clay under TGA.
In situ polymerization approach to multiwalled carbon nanotubes-reinforced nylon 1010 composites: Mechanical properties and crystallization behavior
Abstract A series of polyamide 1010 (PA1010 or nylon 1010) and multiwalled carbon nanotubes (MWNTs) composites were prepared by in situ polymerization of carboxylic acid-functionalized MWNTs (MWNT–COOH) and nylon monomer salts. Mechanical tensile tests and dynamic mechanical analysis (DMA) show that the Young modulus increases as the content of the nanotubes increases. Compared with pure PA1010, the Young's modulus and the storage modulus of MWNTs/PA1010 in situ composites are significantly improved by ca. 87.3% and 197% (at 0 °C), respectively, when the content of MWNTs is 30.0 wt%. The elongation at break of MWNTs/PA1010 composites decreases with increasing proportion of MWNTs. For the composites containing 1.0 wt% MWNTs, the Young modulus increases by ca. 27.4%, while the elongation at break only decreases by ca. 5.4% as compared with pure PA1010 prepared under the same experimental conditions. Compared with mechanical blending of MWNTs with pure PA1010, the in situ-prepared composites exhibit a much higher Young's modulus, indicating that the in situ polycondensation method improves mechanical strength of nanocomposites. Scanning electron microscopy (SEM) imaging showed that MWNTs on the fractured surfaces of the composites are uniformly dispersed and exhibit strong interfacial adhesion with the polymer matrix. Moreover, unique crystallization and melting behaviors for MWNTs/PA1010 in situ composites are observed using a combination of differential scanning calorimetry (DSC) and X-ray diffraction methods. It was shown that only the α-form crystals are observed in our MWNTs/PA1010 in situ composites. This result is quite different from PA1010/montmorillonite and PA6-clay composites, where both of α- and γ-form crystals were found.
Integrated two-beam antenna array featuring dual-circular polarization
A concept of an integrated antenna array featuring two independent beams and dual circular polarization has been described. The antenna array consists of two radiating elements which are excited at two orthogonally placed feeding ports with the use of four appropriately connected 3-dB/90° directional couplers. Therefore, such an array generates two symmetrically located beams having right-handed circular polarization (RHCP) and identical two beams having left-handed circular polarization (LHCP). The presented concept has been verified by the design and measurements of an antenna array operating at 2.4 GHz frequency range.