Dielectric relaxation studies of poly(ethy1ene glycols), average molecular weight 200-9000, have been carried out in carbon tetrachloride solutions at microwave frequency, i.e. 9.83 GHz. Average relaxation times to, and relaxation times corresponding to segmental motion T , and group rotations 72 have been calculated. The variations of relaxation times with increase in degree of polymerization and temperature have been determined. With the increase in the degree of polymerization the flexibility increases and hence the coiling of the chain increases. At a certain temperature there is a decrease in the relaxation time corresponding to segmental motion, suggestive of some switch-over mechanism in higher polymers. The relaxation time corresponding to group rotations is independent of temperature and degree of polymerization.
Dielectric relaxation studies of dialkyl ethers of ethylene glycol and of diethylene glycol have been carried out at microwave frequencies in benzene solutions. Dipole moment and relaxation times corresponding to overall and group rotations and their weight factors have been determined. The configuration of these molecules and the mechanism of the rotation of end alkoxyl groups have been discussed.
The permittivity and dielectric loss of three trichloro esters, namely methyl trichloroacetate, ethyl trichloroacetate, and n-propyl trichloroacetate have been measured at frequencies 1 MHz, 9.83, 18.26, 24.50 GHz, and optical frequency at 35 °C. The permittivity and dielectric loss at different frequencies have been plotted against concentration (weight fraction). The slopes of these straight lines have been used for complex plane plots (a″ vs. a′). There are two possible relaxation processes in these molecules, i.e. overall rotation of the molecule and intramolecular group rotation —CCl3 around C—C bond. Whereas the relaxation time for overall rotation is dependent on temperature the relaxation time for group rotation is practically independent of temperature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.