Effect of olefin length on the type of active centers in Z-N catalysts

Two olefinic monomers with different chain lengths, i.e. 1-hexene and 1-octene, were polymerized using MgCl2/TiCl4 catalyst in slurry conditions in the presence as well as absence of a silane type external donor (ED). After successive polymerizations, effect of monomer length and external donor on the catalyst activity and polymer molecular weights were considered. Higher catalyst activities were obtained in the monomer with shorter chain length, i.e. 1-hexene. Deconvolution of GPC curves showed that by increasing monomer length, MW is decreased but MWD is increased; while that CMMS increased polymer molecular weights but decreased their polydispersity

کلیدواژه ها:

Ziegler Natta catalysts ، higher olefins ، polymerization