| Summary: | 碩士 === 國立中央大學 === 化學系 === 85 === Solid State NMR has proven its utilities in the studies of
polymers, which provide vital information which are not
accessible through other measurements. High resolution solid
state NMR including arrays of tools such as cross polarization,
magic angle sample spinning, multiple pulse, and dynamic angle
sample spinning techniques provide molecular detail regarding
miscibility and specific interactions between blend components.
On the other hand, low field solid state NMR, handicapped with
low frequency resolution, is much more powerful in resolving the
time domain information. Taking advantage of this character, we
have developed a method to reconstruct proton spin-lattice
relaxation time distribution using low resolution solid state
NMR which shows . The features of the distribution profile
provide information regarding the heterogeneity of domain,
structure, morphology and molecular dynamics present in polymer
blend systems. The present study will demonstrate the usage of
T1 spin-lattice time distribution profile method on the study of
morphological changes in two polymer blend systems. The first
system composed of immiscible blends of PVDF and syndiotatic
Polystyrene where the miscibility, re-crystallization, and phase
separation kinetic under various curing temperature and blending
conditions will be studied via proton T1 spin-lattice time
relaxation distribution. The second system pertains to the
polymer solid electrolyte where the detail changes of PEO
crystallinity upon doping with various degree of Li+ cation
concentration is studied by proton spin lattice relaxation time
distribution. These results revealed the kinetics and dynamic
change of the polymers blends are either hard to obtain or no
accessible through conventional measurements.The present results
have fully demonstrated the versatilities, convenience,
sensitivity, and effectiveness of proton spin lattice relaxation
time distribution method in the study of polymer blend systems.
The legitimacy and limitation of this method in the study of
polymer morphology would be thoroughly examined.
|
|---|
