Sl. Abdelmessieh et al., DIELECTRIC-RELAXATION OF DIALKYL FUMARATES MONOMERS HOMOPOLYMERS AND COPOLYMERS IN DILUTE-SOLUTIONS, Journal of molecular liquids, 75(3), 1998, pp. 219-236
The dielectric absorption of some disubstituted ethylenes (dialkyl fum
arates) namely dimethyl fumarate (DMF), diethyl fumarate (DEF), diisop
ropyl fumarate (DIPF), dicyclohexyl fumarate (DCHF), dicyclohexyl male
ate (DCHM), dinonyl fumarate (DNF), didodecyl fumarate (DDF) and dicet
yl fumarate(DCF) has been measured in the microwave region 0.2-18 GHz.
The measurements were carried out at 20 degrees C. The solvent used i
n all cases was CCl4 and the concentration does not exceed 0.003 mole
fraction. The data obtained for the specific absorption Delta epsilon
''/x were analyzed using Debye equation into one or even more than one
relaxation time. The results were interpreted in terms of dipole reor
ientation by molecular and intermolecular rotation. Dielectric measure
ments were also carried for some dialcyl fumarate polymers and copolym
ers in CCl4 solutions at 30 degrees C. The dielectric data revealed th
e existence of three distinct absorption regions related to the main c
hain and its related motions. (C) 1998 Elsevier Science B.V.