Refraction and polarization properties of some fluorinated imidic polymers

Several new fluorinated imidic polymers were analyzed from optical and dielectric point of view. The main achievement of this work consists in the establishment of novel insights in the structure–property correlation by optimization of certain monomer features. Group contribution and Bicerano theories were utilized to calculate molar volume and molar refraction and atomic connectivity indices, respectively. These are further used to obtain the refractive index and from the latter the dielectric constant. Both macromolecular architecture and backbone polarizability affect refraction and polarization properties of specimens. The values of refractive index are reduced by using diamine residues that decrease chain packing and increase density of –CF₃ groups, whereas inserting dianhydride moieties with less bulky character and smaller numbers of low polarizable groups led to the reverse result. The resulted data are important in controlling the physical performance of imidic polymers as demanded by electronic applications.