~(13)C-NMR STUDY ON THE CHAIN TERMINAL STRUCTURE OF POLY-1,3-PENTADIENE POLYMERIZED WITH RARE EARTH CATALYST

The sequence distribution and the terminal structures of poly-1,3-pentadiene chains obtained by rare earth catalyst and effect of polymerization temperature on microstructure of the polymer have been investigated by ~(13)C-NMR method. According to experimental results it was supposed that terminal active growing chain of the polymer would be four types of anti- and syn-η~3-allyl structures. When polymerization temperature was reduced, the content of cis-1,4-poly-1,3-pcntadiene increases. It can be explained by isomerization between anti- and syn-η~3-allyl. The process forming trans-1,2 unit instead of 3,4-unit were also described.

13C-NMR STUDY ON THE CHAIN TERMINAL STRUCTURE OF POLY-1,3-PENTADIENE POLYMERIZED WITH RARE EARTH CATALYST

 The sequence distribution and the terminal structures of poly-1,3-pentadiene chains obtained by rare earth catalyst and effect of polymerization temperature on microstructure of the polymer have been investigated by ¹³C-NMR method. According to experimental results it was supposed that terminal active growing chain of the polymer would be four types of anti- and syn-η³-allyl structures. When polymerization temperature was reduced, the content of cis-1,4-poly-1,3-pcntadiene increases. It can be explained by isomerization between anti-and syn-η³-allyl.The process forming trans-1,2 unit instead of 3,4-unit were also described.