DIELECTRIC-RELAXATION OF DIALKYL FUMARATES MONOMERS HOMOPOLYMERS AND COPOLYMERS IN DILUTE-SOLUTIONS

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.