Two approxns. were made for the vinyl group in the conformational anal. of 1,2-polybutadiene (I): (a) the contribution of the double bond was shared by 2 olefinic carbons and (b) the vinyl group was considered to be spherical in other cases. Conformational energies of meso and racemic dyads of I were computed as function of rotational angles around the skeletal bond. The contours of I were constructed primarily. Truncations did not give evident changes for the topog. and potential surface in the calculation of conformational energies. A simple 3-state scheme was applied to I and the statistical wt. factors were obtained by configurational integral.

Key words: STRUCTURAL ANALYSIS, HIGHPOLYMER, POLYBUTADIENE, CHAIN STRUCTURE, CONFORMATION, STATISTICAL MODEL