负载钛催化合成高反式丁二烯—异戊二烯共聚物的序列分布

Sequence Structure of trans - Butadiene- isoprene Copolymer with Supported Titanium Catalyst Systems

采用TiCl4/MgCl2-Al(i-Bu)3体系催化丁二烯(Rd,M1)-异戊二烯(Ip,M2)共聚合成了高反式-1,4-结构的其聚物,用13CNMR方法研究了共聚物的结构和组成分布,定量计算了共聚物二元组的浓度和数均序列长度,证明共聚物的序列分布服从一级Markov模型,继而根据一级Markov模型预测了一次投料不同转化率下所得共聚物的链段分布?

The high trans - configuration butadiene - isoprene copolymers have been synthesized in the presence of TiCl4/MgCl2 - Al ( i - Bu)(3) catalysts when butadiene mole content in the feed are between 0.055 similar to 0.148. The sequence structures of trans - butadiene - isoprene copolymers have been determined by C-13 NMR spectrometry. The dyad distributions, composition and number - average sequence length of these copolymers are calculated on the basis of assignment of C-13 NMR spectra. The results indicate that the sequence distributions of monomer units in copolymers follow first - order Markov model according to calculations. The products are sequence - irregular copolymers.