COMMERCIAL PROCESSES FOR THE PREPARATION OF LIQUID, LOW MOLECULAR WEIGHT POLYBUTADIENES BY CHAIN TRANSFER AND LIVING MECHANISMS

摘要

Liquid polybutadienes in the MW range of approximately 1 to 10 * 10~3 are produced commercially by anionic polymerisation using both organo-lithium and organo-sodium initiators. The latter are comparatively cheap compared to organo-lithiums but have the disadvantage of limiting the 1,4 microstructure content to a maximum of around 30%. Organo-lithium initiators can provide 1,4 microstructures as high as 90% or as low as 10-20%. via a suitable choice of solvent and/or promoters. They do however represent a high raw material cost for a liquid polybutadiene at the lower end of the above MW range if produced by the classical 'living polymer' mechanism.