Synthesis and characterization of polyaryloxyphosphazene copolymers

Abstract

Abstract A series of polyaryloxyphosphazene copolymers with the general formulas [NP(OC 6 H 5 )(OR)] n and [NP(OC 6 H 4 –4–OCH 3 )(OR)] n , where R = C 6 H 4 –4–CH 3 , C 6 H 4 –4–C 2 H 5 , C 6 H 4 –4–isoC 3 H 7 , C 6 H 4 –4– sec ‐C 4 H 9 , C 6 H 4 –4– tert –C 4 H 9 , C 6 H 4 –4–OCH 3 or C 6 H 4 –4–OC 4 H 9 , have been prepared under anhydrous conditions. Copolymers as well as selected homopolymers were prepared by the reaction of polydichlorophosphazene with appropriate sodium aryloxides. Each of the polymers was characterized by elemental analysis, infrared spectroscopy, gel–permeation chromatography, and differential scanning calorimetry. Elemental analysis established the empirical formula for the polymers and showed that there were no residual PCl bonds left on the polymer backbone. Infrared spectroscopy indicated the presence of a phosphorus–nitrogen backbone with two aryloxy groups bonded to each phosphorus atom. The copolymers examined exhibited molecular weights of above 1 × 10 6 . Polyaryloxyphosphazene copolymers were examined by differential scanning calorimetry and compared to several of the corresponding homopolymers. Glass transition temperatures ranged between −34 and +44°C for the polymers. The Kelley‐Bueche equation was used to predict the glass transition temperatures of the copolymers. Close agreement was found between calculated and experimental values for most of the systems examined.