INDEX unsupported

Keii119> studied recently the effect of polymerization time, hydrogen, donor and aluminum alkyl on the MWD of propylene obtained with the MgCl2/TiCl4/EB— AlEtj/EB catalyst system. The isotactic and atactic fraction polydispersity indexes were found to be independent of the above parameters, and very close to each other (Mw/Mn = 3-5) as previously reported by Suzuki133) and Kashiwa,34). The Mw/Mn values of the overall polymer are lower than in the case of TiCl3 and are better represented by a Wesslau-type log-normal correlation than by a Tung-type correlation, as is the case of unsupported catalysts. 

For single crystal surfaces, a reaction is deemed insensitive if its rate is about the same on all low Miller index planes, but since these differ from small metal particles in not having atoms of very low co-ordination number, the term face sensitivity should be used in this case. Two further approaches to the general problem have been tried (1) systematic variation of particle in supported metal catalysts, and (2) alteration of the composition of the surface of bimetallic catalysts, either supported or unsupported (Section 5.7). These lead respectively to particle size sensitivity and ensemble size sensitivity, but the three types are not necessarily exactly the same. 

---