Polymerization of 3‐vinylpyrene with Ziegler‐Natta catalyst

Using a Ziegler‐Natta catalyst, we obtained a polymer of 3‐vinylpyrene having large π‐electron systems as pendant groups. The conversion was highest at AlEt3/TiCl4 = 1/1, being ca. 90%. It was lower with TiCl4 alone, and was also reduced down to ca. 30% at Al/Ti = 7/1. The conversion exceeded 80% after only 7 hr. at Al/Ti = 2/1. This polymer has a melting point of 214°C. determined by a polarizing hot‐stage microscope examination. X‐ray examination showed that this polymer is crystalline, although rather poor. The polymer is soluble in many solvents. From the similarity of ultraviolet absorption spectra of 3‐ethylpyrene and polyvinylpyrene prepared by benzoyl peroxide (BPO), TiCl4, AlEt3–TiCl4, this polymer is believed to have a linearly combined chain structure with a large pendant pyrene nucleus and to have no crosslinking at all.