Sequences in Polyisoprene

The large numbered peaks produced upon Py-GC reflect the many possible transfer reactions for this polymer some of which are illustrated next. Hydrogen transfer reactions which occur from the fifth carbon atom predominate as indicated by the large butane, 3-methyl hexane and 2-methyl heptane peaks  

Hydrogen transfer also from the ninth carbon atom, which is shown by the size of the 3-methyl nonane, 3,7-dimethyldecane and the 2,6-dimethylundecane peaks  

The technique has been applied to various unsaturated polymers. Thus, polyisoprene, having nearly equal 1,4 and 3,4 structures, produced large amoimts of laevulinaldehyde, succinaldehyde and 2,5 hexanedione, indicating blocks of 1,4 structures in head-tail, tail-tail and head-head configurations. 

Thus the ozonide of the tail-to-tail 1,4 configuration upon ozonisation and hydrolysis yields succinaldehyde (CHO-CH2-CH2-CHO). Similarly, the ozonides of the head-to-tail and head-to-head configurations yield laevulinaldehyde (CHO-CH2-CH2-CO-CH3) and 2,5-hexane dione (-CH3-CO-CH2-CH2-CO-CH3), respectively. 

Boochathum and co-workers [30] applied ozonisation-gel permeation chromatography (GPC) to a study of the structure of solution grown trans 1,4-poyisoprene crystals. 

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