MOLECULAR-INTERACTIONS IN PERFLUORINATED AND HYDROGENATED COMPOUNDS - LINEAR PARAFFINS AND ETHERS

The cohesive energy density (CED) of linear hydrogenated and perfluorinated paraffins and ethers has been investigated with regards to its dependence on chain length and oxygen content. For high molecular weight compounds (i.e., polymers) the CED has been obtained by extrapolation or by the group contribution method. The oxygen contribution to cohesive energy is found to be very different in the hydrogenated ethers with respect to the perfluorinated ones, and, correspondingly, the dependence of CED on the oxygen to carbon ratio (O/C) is the opposite for the two series. A similar trend, previously described for the glass transition temperature (T(g)) is therefore roughly interpretable as related mostly to CED. although intramolecular flexibility parameters also play a role.