Preparation and properties of copolyamides‐6,6F and copolyamides‐4,8F containing oligo(tetrafluoroethylene)segments

Two families of copolyamides‐6,6F and copolyamides‐4,8F containing various amounts of bis‐ and tris(tetrafluoroethylene) segments were prepared to study the influence of such fluorine‐containing segments on bulk and surface properties. In a solution polycondensation process telechelic aliphatic diamines, obtained by reacting dimethyl α,ω‐dicarboxylatooligo(tetrafluoroethylene)s with excess diamines, e. g., tetramethylenediamine and hexamethylenediamine, were polymerized with activated bis(4‐nitrophenyl) adipate and bis(4‐nitrophenyl) suberate. In the presence of various stoichiometric amounts of the aliphatic diamines, the fluorine content varied between 0 and 39 wt.‐% and the inherent viscosities between 0,27 and 1,02 dL/g. As content and segment length of the oligo(tetrafluoroethylene) segments increased, the polymer solubilities in organic solvents and the contact angles to water increased, whereas melting temperatures, crystallinities (as measured by means of differential scanning calorimetry and wide‐angle X‐ray scattering (WAXS)) and thermal stabilities (as determined by means of thermogravimetric analysis of the weight loss encountered at elevated temperatures) were reduced markedly. The WAXS measurements reflected changes of crystal structures with increasing fluorine content.