| dc.description.abstract | Dielectric relaxation and infrared study of a number
of associating (H-bonding) compounds in glassy media,
mainly polystyrene, have been carried out. The dielectric
measurements by a General Radio 1621 Precision Capacitance
bridge and infrared measurements by a Beckman spectrophotometer
IR4250 have been described. The experimental dielectric data
as a function of frequency at different temperatures were
subjected to analysis by a series of computer programs written
in APL and BASIC languages. The activation energy barriers
opposing the dielectric relaxation processes were obtained
by the application of the Eyring rate equation.
An infrared study of various sterically hindered
alcohols in polystyrene have been carried out. It is shown
that a decrease in temperature leads to an increase in the
degree of polymerization. The effect of steric factors on
the degree of polymerization at a given temperature has also
been discussed.
Dielectric studies of sterically hindered alcohols,
mainly in polystyrene matrix, have yielded, in some cases,
completely separated molecular and intramolecular processes due to the H-bonded species. All alcohols gave a process
owing to the H-bonded species with the exception of the most
sterically hindered di-tert-butyl carbinol, tricyclohexyl
carbinol and diphenyl methyl carbinol. The presence of Hbonded
species was indentified by the infrared spectrum of
the sample. In addition to sterically hindered alcohols, some
simple small alcohols and water were also studied in a polystyrene
matrix and in some other glassy media. The process
owing to the H-bonded species was found to occur in the
similar temperature region as was observed for sterically
hindered alcohols. The energy barriers of the process related
with H-bonded species for all the alcohols and water in a polystyrene were of a similar order of magnitude. A possible
mechanism for the process related to H-bonded species was
discussed.
Dielectric studies on alcohol and amine systems in a
polystyrene matrix have been carried out. It has been discussed
that alcohols interact with amines, thus increase the dipole
moment of the complexes which leads to an increase in the
dielectric loss factor of the system. However, in many cases
the dielectric process due to the complex, formed by alcoholamine
interaction, was overlapped with the absorption owing
to the H-bonded species of the alcohol and/or to the molecular
process of amine. | |
