*2.1.3. Organoclay-modified as-recieved TLCP (TC3 white) preparation*

Initially, TLCP was dried in a vacuum oven at 120 oC for 2 days and organoclay in an oven at 100 oC overnight. The materials were dissolved and dispersed in chloroform respectively with a TLCP/organoclay weight ratio 97:3. The solutions were then stirred for about 4 hours at room temperature. After that, TLCP and organoclay were mixed together and the mixture was sonicated by ultrasonic pin vibration (Branson digital sonifier 450, USA) with 45% power for about 2 hours at room temperature. Subsequently, the mixture was centrifuged with a speed of 3,800 rpm for 45 minutes to separate the bottom layer precipitate which was believed to be redundant organoclay and unsolvable TLCP, and the top layer, if any, which was believed to be impurities in TLCP, from the middle portion; then the solvent was volatilized at room temperature. A nanocomposite was obtained, which was dried in an oven at 60 oC for 12 hours and in a vacuum oven at 120 oC for 2 days. The nanocomposite showed severe shear-induced phase separation phenomenon at 190 oC or higher temperatures and can be effectively separated by a capillary rheometer at 190 oC at a low speed (5.0 1/s) [21]. The extruded material was named TC3 white because of its white color, which will be used here for study.

Micro-Rheological Study on Fully Exfoliated Organoclay Modified Thermotropic Liquid Crystalline Polymer and Its Viscosity Reduction Effect on High Molecular Mass Polyethylene 279

scale using tetramethylsilane (TMS) as the

procedure. The 13C nuclear magnetic resonance (NMR) spectra were measured at room temperature on a Bruker ARX 300 NMR spectrometer using chloroform-d as the solvent,

The mesophase structures of the liquid-crystalline phase of TLCP and its nanocomposite were investigated by polarized optical microscopy (POM) using an Olympus microscope BX 50 with a Cambridge shear system CSS450 connecting a hot stage. The most outstanding feature of this setup is that it allows investigation of texture changes at different temperatures and under varying shear rates. Mesophase structure images were obtained at 185 oC after preshearing samples with a low shear rate i.e. 0.5 1/s for more than 3600 seconds to remove any shear history and anchored defects, and to give a common shear history or structure to samples before isothermal treatment in a quiescent condition for sufficient time.

Thermal stability analysis was carried out by using a Hi-Res TGA 2950 thermogravimetric analysis (TGA) apparatus (TA instruments, USA). The test was carried out in air with a heating rate of 20.0 oC/min from 50.0 oC to 600.0 oC, and then isothermally treated for 30 minutes at 600.0 oC. The phase transition temperature of the nanocomposite based on TLCP was determined via differential scanning calorimetry (DSC) (PYRIS diamond DSC, Perkin-Elmer Instruments, USA), using indium as the calibration standard, with heating or cooling

Controlled strain rheological measurements were carried out using an advanced rheometric expansion system (ARES) (TA instruments, USA) with a 200 g-cm transducer within the resolution limit of 0.02 g-cm. 50 mm cone and plate fixtures with nominal cone angle 0.04 rad and nominal gap 0.0508 mm, as well as 50 mm parallel plate fixtures were used for TLCP and its nanocomposite reported here. All measurements were performed at 185 C in N2 atmosphere, where TLCP had been shown to exhibit stable rheological properties under the nematic phase. Care was taken to ensure a controlled thermomechanical history as follows: the rheometer was heated to the testing temperature and allowed to reach equilibrium. Fresh samples, dried in a vacuum oven for 2 days at 120 oC, were loaded in the preheated rheometer, heated up to 185 oC then held for 10 minutes. Decreased gap to the testing gap and kept isotherm for 30 minutes to reach thermal and deformation equilibrium before measurements were started. The experiments were repeated no less than three times to check reproducibility. In each case, a fresh sample was used. For all tests reported here on HMMPE blends, 25 mm parallel plate fixtures were used. All measurements were performed at 190 C with a 2000 g-cm transducer within the

*2.2.4. Thermogravimetric analysis & differential scanning calorimetry* 

*2.2.5. Advanced rheometric expansion system and capillary rheometer* 

and the chemical shifts were reported on the

rate of 10.0 oC/min under nitrogen atmosphere.

*2.2.3. Polarized optical microscopy* 

internal reference.
