Trans-stereospecific polymerization of butadiene and random copolymerization with styrene using borohydrido neodymium/magnesium dialkyl catalysts

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• 作者：A. Ventura ; T. Chenal ; M. Bria ; F. Bonnet ; P. Zinck ; Y. Ngono-Ravache ; E. Balanzat ; M. Visseaux
• 关键词：Stereospecific polymerization ; Trans-polybutadiene ; Styrene-butadiene copolymer ; Rare earths ; Microstructure ; NMR
• 刊名：European Polymer Journal
• 出版年：December, 2013
• 年：2013
• 卷：49
• 期：12
• 页码：4130-4140
• 全文大小：1528 K

文摘

The combination of a neodymium borohydride, Nd(BH₄)₃(THF)₃ (rong class="boldFont">1rong>) or Cp^*Nd(BH₄)₂(THF)_x (rong class="boldFont">2rong>), with MgⁿBuEt (BEM), affords an efficient and highly selective (up to 96.7% 1,4-trans) catalyst for butadiene polymerization. In the presence of excesses of Mg co-catalyst, polymer chain transfer takes place between neodymium and magnesium, and significant amounts of 1,2-units are observed. When considered for butadiene-styrene statistical copolymerization, the catalytic system based on rong class="boldFont">2rong> showed a good ability to produce poly[(1,4-trans-butadiene)-co-styrene)], with strong impact of the Mg/Nd ratio on the yield and on the copolymer microstructure, including the percentage of inserted styrene (up to 16.9 mol%). Whatever the co-monomers concentration the polybutadiene backbone remained 1,4-trans. The precise microstructure of the polymers and copolymers was thoroughly analyzed by means of high resolution NMR spectroscopy (900 MHz) and MALDI-ToF spectrometry.