Glass transition phenomena in two-component plastic crystals: Study of hexasubstituted benzenes

Article Abstract:

The relaxation that is known to occur in the crystalline phase of pentachloronitrobenzene (PCNB) and 2,3,4,5,6-pentabromotoluene (PBT) is critically examined using dielectric spectroscopy and differential scanning calorimetry. Findings suggest that the hexasubstituted benzenes or their binaries do not reveal any well resolved secondary relaxation in their plastic crystalline phases within the resolution of the experimental setup and that the T dependence of the relaxation rate deviates from Arrhenius character near [T.sub.g] in PBT, PCNB, and PCT.

Petrochemical Manufacturing, Benzene, Usage, Spectrum analysis, Spectroscopy

---

Relaxation dynamics of orientationally disordered plastic crystals: effect of dopants

Article Abstract:

The relaxation occurring in the supercooled plastic crystalline phases of pentachloronitrobenzene (PCNB), dichlorotetramethylbenzene (DCTMB), trichlorotrimethylbenzene (TCTMB) along with some of their deuterated samples and 1-cyanoadamantane (CNADM) is examined in the presence of dopants. The studies have shown that the changes in the dielectric strength of the [alpha]-process is because of the rotational hindrance caused by the presence of a small number of dopant molecules in the host crystalline lattice.

Cyclic crudes and intermediates, Cyclic Crude and Intermediate Manufacturing, Nitrobenzene, Observations, X-rays, X-ray diffraction, Nitrobenzenes, Chlorine compounds

---

Dielectric and calorimetric study of orientationally disordered phases in two unusual two-component systems

Article Abstract:

Low-frequency dielectric spectroscopy and differential scanning calorimetry (DSC) are used for examining two unusual two-component solid solutions, where one is hydrogen (H-)-bonded pair and the other is a non-H-bonded pair. The relaxation phase observed in the plastic phase I of the cyclooctanol (COOL)-cycloheptanol (CHOL) binary system has corresponded to the [alpha] process, whose kinetic freezing has caused the glass transition event.

Science & research, Research, Spectra, Hydrogen bonding, Hydrogen bonds, Thermal properties, Cyclic compounds, Dielectric relaxation

Similar abstracts:

• Abstracts: Electron transport in coumarin-dye-sensitized nanocrystalline TiO(sub 2) electrodes. Molecular rotation at negatively charged surfactant/aqueous interfaces
• Abstracts: Requirements for the formation of a chiral template. First-principles study of K and Cs adsorbed on Pd(111). Mixed aromatic-alkyne system on a Pd surface: A first-principles study
• Abstracts: Calculations on the electronic excited states of ureas and oligoureas. Significant conformational changes associated with molecular transport in a crystalline solid
• Abstracts: Length dependent helix-coil transition kinetics of nine alanine-based peptides. Conformational distribution of a 14-residue peptide in solution: A Fluorescence resonance energy transfer study
• Abstracts: Magnetic orientation of benzophenone crystals in fields up to 80.0 KOe. On the movement of paramagnetic ions in an inhomogeneous magnetic field

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.