Preparation and properties of isomeric polyphenylacetylenes

Abstract

Abstract Polyphenylacetylenes were prepared using ferric acetylacetonate and (i‐Bu) 2 AlH, RhCl[(C 6 H 5 ) 3 P] 3 and thermal initiation. Color, infrared spectra, softening temperatures, ultraviolet fluorescence, solubility, and crystallinity are described. A method is presented for assigning to these three macromolecular species predominantly cis , trans , and cis – trans copolymer structures, respectively. The dominantly cis polymer is believed to form in a transoid conformation which can easily be transformed to a more helical arrangement which exhibits a degree of crystallinity. Pyridine promotes the isomerization of cis to trans structure. The rhodium phosphine is thought to effect chain growth by repeated additions of the acetylenic CH of monomer across a terminal triple bond. Phenylacetylene thus behaves as a bifunctional molecule in this system. Color, polymer conformation, and crystallinity appear to be strongly interrelated.