The 13C-NMR

spectra of alternating copolymers of conjugated dienes

e.g. butadi-ene(BD)

isoprene(IP) and chloroprene(CP)

with methyl acrylate(MA) were studied. It was proved that they are all alternating copolymers. The BD units in poly(BD-a-Ma) are mainly in the form of trans-1

4-structure. The contents of trans-1

4-

cis-1

4- and 1

2-structure are 88

7 and 5%

respectively. The IP and OP units in poly(IP-a-MA) and poly(CP-a-MA) are present essentially in trans-1

4-configuration and link with MA units predominantly in the "head to head"arrangement while CP-CP units pre-sent in the latter with a small quantity.