Intermediate Physical State of Gel And LC In Cellulose Solution And Its Synergetic Effects

In this study, the physical state of cellulose in solution was analyzed via rheological observations under three different conditions, i.e. steady state, small amplitude oscillatory shear, and large amplitude oscillatory shear conditions. The physical states of the solution were changed from isotropic phase to gel structure via liquid crystalline (LC) phase as the concentration increased. The rheological analysis showed that the solution of 16 wt% was physically gelled at the anisotropic phase. This instantaneous gelation at the LC phase dramatically enhanced the mechanical performance of the film obtained from the solution. The study provides a fundamental strategy for the huge improvement of the mechanical properties of the cellulose fibers or films.

Thermotropic Copolyesters Based on Polyethylene Terephthalate and 4-Hydroxybenzoic Acid for High Modulus Fibers

The copolyesters derived from dimethyl ester of terephthalic acid, ethylene glycol, and 4-hydroxybenzoic acid (HBA) have been synthesized via catalytically promoted polycondensation omitting the acetylation step. FTIR spectroscopy results have evidenced an insertion of HBA along a polymer backbone. Of note, thermal gravimetric analysis has shown that the HBA moieties substantially improved the thermal stability of polyesters. As found by differential scanning calorimetry and polarizing microscopy, the copolyesters are capable of forming an anisotropic phase in a temperature range of 150-170 °C. Additionally, the free surface energy of the samples was determined to evaluate the compatibility of thermotropic copolyesters with other high-molecular compounds.

Large-scale variation in seismic anisotropy in the crust and upper mantle beneath Anatolia, Turkey

The average anisotropy beneath Anatolia is very strong and is well constrained by shear-wave splitting measurements. However, the vertical layering of anisotropy and the contribution of each layer to the overall pattern is still an open question. Here, we construct anisotropic phase-velocity maps of fundamental-mode Rayleigh waves for the Anatolia region using ambient noise seismology and records from several regional seismic stations. We find that the anisotropy patterns in the crust, lithosphere and asthenosphere beneath Anatolia have limited amplitudes and are generally consistent with regional tectonics and mantle processes dominated by the collision between Eurasia and Arabia and the Aegean/Anatolian subduction system. The anisotropy of these layers in the crust and upper mantle are, however, not consistent with the strong average anisotropy measured in this area. We therefore suggest that the main contribution to overall anisotropy likely originates from a deep and highly anisotropic region round the mantle transition zone.