LINEAR NONCONJUGATED DIENES FROM BIOMASS AS TERMONOMERS IN EPDM SYNTHESIS .1. STUDY OF THEIR REACTIVITY IN HOMOPOLYMERIZATIONS, COPOLYMERIZATIONS AND TERPOLYMERIZATIONS

This paper deals with the use of 3,7-dimethylocta-1,6-diene (3,7-DMO) and 5,7-dimethylocta-1,6-diene (5,7-DMO), issued from terpene feedstoc k, as termonomers for the synthesis of ethylene-propylene-diene terpol ymers (EPDM). Their reactivity is first compared to 7-methylocta-1,6-d iene (MOCD), an industrial linear diene, in homopolymerization and cro ss-copolymerization. Two catalytic systems are used: TiCl3, 1/3AlCl(3) , 14MgCl(2), associated with Al(C2H5)(3), and VOCl3 or VCl4 associated with Al(C2H5)(2)Cl. The influence of the diene structure on the obser ved order of reactivity is discussed. In a second part, the copolymeri zation and the terpolymerization of the different dienes with ethylene and propene are implemented. A drastic influence of the diene structu re and concentration on the productivity (and activity) is observed. P otentiometric titrations of the vanadium, performed both in the absenc e and in the presence of dienes (and of other substituted olefins), in dicate that the productivity loss mainly results from a reduction proc ess of the vanadium, involving the di- or trisubstituted olefins.