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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 2481-2491 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The synthesis in the presence of the rac-EtInd2ZrCl2/MAO catalytic system of new EPDM terpolymers based on linear non-conjugated dienes issued from biomass, 3,7-dimethylocta-1,6-diene (3,7-DMO) and 5,7-dimethylocta-1,6-diene (5,7-DMO), is described. 5,7-DMO can be readily incorporated in ethylene/propylene (E/P) chains, while 3,7-DMO does not react in the presence of the metallocene catalyst. The reactivity of these linear dienes is compared with that of 2-ethylidenebicyclo[2.2.1]hept-5-ene (ENB), the preferred termonomer for the industrial synthesis of EPDMs. With the metallocene catalyst, the reactivity of 5,7-DMO is close to that of ENB, suggesting that 5,7-DMO is a good candidate for the synthesis of a new EPDM. A comparison with the conventional catalysis based on vanadium systems shows that the advantages of the metallocene catalysis consist in higher catalyst activities and higher incorporation rates of the termonomers in the polymer without any noticeable side reaction. The structural and physico-chemical characteristics of the various terpolymers, investigated by NMR, SEC and DSC, also underline that the use of metallocenes allows one to prepare EPDM based on linear dienes, with an homogeneous chemical composition and a controlled structure.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 289-302 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A comparative study of 5-ethylidene-2-norbornene (ENB) or 5,7-dimethylocta-1,6-diene (5,7-DMO) as diene termonomer in ethylene-propylene-diene (EPDM) terpolymer synthesis is presented. The reactivities of the cyclic and linear non-conjugated dienes are first compared in homopolymerization in the presence of two conventional Ziegler-Natta catalytic systems: TiCl3, 1/3AlCl3, 14MgCl2 associated to AlEt3, and VOCl3 (or VCl4) associated to AlEt2Cl. ENB polymerization yields a branched poly(ENB) in agreement with a predominant cationic reaction, whereas polymerization of 5,7-DMO proceeds exclusively by a Ziegler-Natta mechanism. In terpolymerization, ENB is much more reactive than 5,7-DMO and is incorporated more easily in the terpolymer. However, the high sensitivity of ENB toward acidic species also results in cationic side reactions and therefore limits the utilization of ENB to a low concentration range. We have shown that the productivity of vanadium catalysts, which are mainly used in industrial EPDM synthesis, is drastically reduced in the presence of ENB an 5,7-DMO, due to the rapid reduction of vanadium involving the diene.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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