NMR study on the chain structure of cyclized CIS -1,4 - polybutadiene

It is proved clearly by using H-H COSY that there is the three-substituted bond in the end of polycyclic sequences of cyclized cis-1, 4 polybutadiene. On the other hand, a little of trans -1,4 and 1,2-units of polybutadiene are comprised in the residue linear chain of cyclized cis-1,4 polybutadiene as shown in its ¹³C NMR spectrum. Based on information provided by H - H COSY, assignment of the high-resolution ¹H NMR spectrum of cyclized cis -1, 4 polybutadiene is obtained finally. In order to get the degree of cyclization (X) and the cyclicity (Y) of cyclized cis -1,4 polybutadiene two parameters P and Q are defined. In the same time, the relationship between X, Y and P, Q are discussed and the formulas calculated X and Y are provided. The method proposed in this paper is satisfactory to investigation of its microstructure and physical, physical-chemical properties.