| Abstract: | The technique of microozonolysis followed by gas chromatography has been used to determine the amount of 1,2-structures occurring as 1,4–1,2–1,4 sequences in n-butyl-lithium-initiated polybutadienes. The product obtained from the ozonolysis of these sequences, 3-formly-1,6-hexanedial, was directly proportional to the 1,2 (vinyl) content of the polymers as measured by infrared or NMR spectroscopy. An unusual ozonolysis product, 4-octene-1,8-dial, has been found in the ozonolysis products of high-1,4 poly-butadienes. Ozonolysis has also been used to determine alternating structures in propylene-butadiene copolymers. The product obtained from ozonolysis of such structures is 3-methyl-1,6-hexanedial. Ozonolysis of a polyisoprene containing equal amounts of 1,4 and 3,4 structures indicated it to have a nonalternating structure with long blocks of 1,4-isoprene units. Gas chromatographic separation was accomplished by using sucrose acetate isobutyrate with Carbowax 20M as the liquid phase. Retention times were established by using model compounds where possible. |
