Butadiene polymerisation using binary neodymium-based catalyst systems. The effect of catalyst preparation

In situ X-ray absorption fine structure study on the polymerization of isoprene assisted by Nd-based ternary catalysts

“…Based on the in situ XAFS experiments, the extracted structure parameters around Nd center support strongly the catalyst activation and propagation mechanism of previous researches. 23,[29][30][31][32] Kwag 17 also illustrate the polymerization process of NDH, i.e., Nd(OOCR) 3 $(HOOCR), there is no oxygen bonded to the Nd center aer chlorination and the butadiene polymerization should be changed into isoprene polymerization, which are slightly different with our result. The catalytic mechanism for IP polymerization can be speculated as follows.…”

“…Based on the structure analysis of Nd precursor by matrixassisted laser desorption ionization time-of-ight (MALDI-TOF) mass spectrum, Kwag 17 considered that the dissociated monomeric structure of Nd(vers) 3 $(neodecanoic acid) is the reason to have a higher activity, and a catalyst activation and propagation mechanism was depicted. Many researches 23,[29][30][31][32] speculated that the insertion and propagation of polymer chain between the Nd center and the alkyl group facilitate the polymerization reaction, which is because of the high number of coordination possibilities at the Nd atom through the vacancies on its "4f" orbitals and the unstable Nd-C bond in the catalyst being replaced by the much more stable p complex through reaction. Fischbach et al 26 investigated the dynamic behavior of the tetraalkylaluminate ligand and the coordination features of heteroleptic mono-and bis(tetraalkylaluminate) complexes through variable-temperature NMR studies and X-ray crystallographic analyses.…”

Influência das características estruturais sobre a processabilidade do polibutadieno alto cis

“…Os sistemas à base de neodímio [8][9][10][11][12] permitem uma extensiva e controlada variação dos parâmetros estruturais e conseqüentemente, das propriedades dos compostos vulcanizados. A distribuição de peso molecular pode variar entre os dois extremos, desde muito estreita até muito larga ( n M w M entre 2 e 20), assim como o grau de ramificações pode variar entre os limites considerado muito baixo e alto (entre 3 e 20%).…”

Polymerization of 1,3-butadiene with neodymium chloride tripentanolate/triisobutylaluminum binary catalyst system: effect of aging time and reaction temperature

“…For instance, Iovu et al [7,8] evaluated the binary system NdCl 3 tributyl phosphate/triisobutylaluminum (TIBA) on the polymerization of butadiene, in which they observed the highest catalytic activity when the catalyst was synthesized in the presence of precise and small amounts of butadiene, an aging time of 1 h and reaction temperature of 20°C. Srinivasa et al [9] evaluated the binary system NdCl 3 2-ethylhexanolate/triethylaluminum on the polymerization of butadiene at different 2-ethylhexanol/Nd molar ratios, observing a higher activity when a ratio of 2.5 was employed.…”