Molar Mass Control by Diethyl Zinc in the Polymerization of Butadiene Initiated by the Ternary Catalyst System Neodymium Versatate/Diisobutylaluminum Hydride/Ethylaluminum Sesquichloride

Modeling of Isoprene Solution Coordinative Chain Transfer Polymerization

“…The living character of the polymerization at different reaction conditions for experimental and model data is evidenced in Figure 22, which shows the linear relationship between −ln(1 − x) and polymerization time, common to the coordinative chain polymerization. [12,39,40] Particularly the model data show a perfectly linear relationship because of the proposed kinetic mechanism and absence of deviations caused by experimental errors. Although the model fitted well the average molecular weights and the monomer conversion values at different reaction conditions, the molecular weight distribution calculated by the model (solving a sufficiently high number of mass balance equations for chains of different sizes) did not represent the experimental molecular weight distributions appropriately, as one can see in Figure 23.…”

“…The living character of the polymerization at different reaction conditions for experimental and model data is evidenced in Figure 22 , which shows the linear relationship between and polymerization time, common to the coordinative chain polymerization. [ 12,39,40 ] Particularly the model data show a perfectly linear relationship because of the proposed kinetic mechanism and absence of deviations caused by experimental errors.…”

“…Most literature studies devoted to modeling of the coordinative chain transfer polymerization involve the polymerization of olefins. [10,13,[33][34][35][36][37][38] Concerning the modeling of the CCTP of 1,3-dienes, some studies described the CCTP of 1,3butadiene, [12,39,40] and the CCTP of isoprene, [41] with help of empirical data driven models. To the best of our knowledge, there is no mechanistic modeling study about the solution isoprene coordinative chain transfer polymerization available in the literature.…”

Coordinative Chain Transfer Polymerization

“…CCTP of conjugated dienes was mainly reported to be 1,4-cis stereoselective. [55][56][57][58][59][60][61] The transmetalation of a growing polydiene chain could be accompanied by a decrease of the 1,4-cis selectivity of the reaction. Rare earth trichloride adducts and versatate were among the most studied precatalysts in the presence of aluminum and zinc based chain transfer agents.…”

Lanthanide Metal‐Organic Frameworks as Ziegler–Natta Catalysts for the Selective Polymerization of Isoprene

“…At higher temperatures, however, the value of initiation efficiency appears far higher than 100% (i.e., run 12: M exp n ¼ 17 000, M th n ¼ 50 000), which suggests the probable occurrence of transfer reactions between Nd and Al during the polymerization process, as already observed with Nd/Al combinations. [25] In order to assess the occurrence of Nd leaching after MMAO treatment, a polymerization experiment was carried out with the filtrate of a toluene MIL-103(Nd)/ MMAO mixture (run 15). The very poor yield of polymer recovered (less than 7%) shows that the catalysis is rather a heterogeneous than a homogeneous one, most active species remaining supported onto the mineral phase.…”