Accession Number:
ADA167063
Title:
NMR Study of Disordered Materials under Extreme Conditions of Pressure and Temperature
Descriptive Note:
Final rept. 1 Oct 1980-30 Sep 1985
Corporate Author:
ILLINOIS UNIV AT URBANA DEPT OF CHEMISTRY
Personal Author(s):
Report Date:
1986-02-05
Pagination or Media Count:
20.0
Abstract:
A new NMR method for measuring the crystallization kinetics of polymers under high pressure, sensitive on a molecular scale to the dynamics of chain motion, was developed. The very rapid formation of extended chain crystals of polyethylene was directly observed. The techniques has much promise for future experiments including polymer crystallization, melting and annealing. Polarization microscopy and NMR experiments on various alkali salts of alkalicarboxylates elucidated the dynamic structure of the smectic phase of these interesting ionic liquid crystalline materials. Experiments on highly viscous liquids explained the origin of the anomalous discontinuity observed in the temperature dependence of the shear viscosity of glass forming liquids. Molecular level interpretation of the coupling between translational and rotational motions in viscous liquids was achieved. The Debye and Stokes-Einstein equations were found to be applicable at the molecular level in viscous liquids. Volume effects were shown to be important for dynamics of viscous liquids.
Descriptors:
- *CRYSTAL STRUCTURE
- *CRYSTALLIZATION
- *NUCLEAR MAGNETIC RESONANCE
- *ORDER DISORDER TRANSFORMATIONS
- *POLYMERS
- *SALTS
- ALKALI METAL COMPOUNDS
- ANNEALING
- ANOMALIES
- CHAINS
- CRYSTALLOGRAPHY
- CRYSTALS
- DISCONTINUITIES
- DYNAMICS
- GLASS
- HIGH PRESSURE
- IONIC CRYSTALS
- KINETICS
- LIQUID CRYSTALS
- LIQUIDS
- MATERIALS
- MICROSCOPY
- MOLECULAR STATES
- MOLECULES
- MOTION
- POLARIZATION
- POLYETHYLENE
- PRESSURE
- SHEAR PROPERTIES
- TEMPERATURE
- VISCOSITY
- VOLUME
Subject Categories:
- Crystallography
- Atomic and Molecular Physics and Spectroscopy