High-Resolution Proton Magnetic Resonance Analysis of Polypropylenes

The dyad and triad tacticities of polypropylenes were determined quantitatively with the aid of a computer form the 100-MHz proton magnetic resonance spectra in o-dichlorobenzene solution at 165ddot]C. The contents of tactic dyad and traid evaluated from the 100-MHz PMR spectra are in fair agreement with the values determined from the 220-MHz PMR and ¹³C-(¹H) spectra, respectively. The fraction soluble in boiling ethyl ether of polymer prepared with the Ti(O-n-Bu)Cl₃-AlEt₂ Cl catalyst shows a character of stereorandomness, and the ethyl ether-soluble portion of polymer polymerized with the TiCl₃-AlEt₂ Cl catalyst has a character of stereoblock sequence. Furthermore, by IR analysis, it has become apparent that the former has a (CH₂)₂ group formed by two propylene units in a tail-to-tail arrangement.