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 feedstock, as termonomers for the synthesis of ethylene-propylene-diene terpolymers (EPDM). Their reactivity is first compared to 7-methylocta-1,6-diene (MOCD), an industrial linear diene, in homopolymerization and cross-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 observed order of reactivity is discussed. In a second part, the copolymerization and the terpolymerization of the different dienes with ethylene and propene are implemented. A drastic influence of the diene structure and concentration on the productivity (and activity) is observed. Potentiometric titrations of the vanadium, performed both in the absence and in the presence of dienes (and of other substituted olefins), indicate that the productivity loss mainly results from a reduction process of the vanadium, involving the di- or trisubstituted olefins.