摘要
研究了聚合物载体-钕络合物-氯代烷-三异丁基铝新体系用于共轭双烯的聚合,所用载体为苯乙烯-丙烯酸共聚物。丁二烯聚合时体系的催化活性的大小既取决于氯代烷的种类,又与配制催化剂的溶剂有关。聚合物载体-钕络合物体系的活性高于小分子异辛酸钕和环烷酸钕体系。氯代烷的种类不影响所得聚合物的微观结构。体系保持了小分子稀土催化剂所具有的良好定向效应,所得聚丁二烯的顺式-1,4结构含量高于98%。采用这一体系得到的聚异戊二烯的顺式-1,4结构含量在96%左右。载体本身的组成及其络合物中稀土的含量对体系的活性影响很大。
A new type of catalyst system comprising styrene-acrylic acid co-polymer supported neodymium complex (SAAC·Nd), alkyl chloride and triisobutylaluminium for conjugated dienes polymerization was prepared, and the effect of seven alkyl chlorides (butyl chloride, isobutyl chloride, isoamyl chloride, carbon tetrachloride, allyl chloride, beuzyl chloride and triphenylchloromethane) as the third component on the catalytic activity was compared. The activity of the catalyst system for the polymerization of butadiene depends on the kinds of alkyl chloride, as well as on the solvent used in the catalyst preparation. Different kinds of alkyl chloride have no obvious effect on the microstructure of obtained polymer. The highest activity of the catalyst system and the smallest value of intrinsic viscosity of the polymer were found when Ph3CCl was used as the third component at gramatom ratio of Cl/Nd = 3-5. Along with the increasing of Al/Nd molar ratio, the activity of the catalyst system increased and the intrinsic viscosity of polybutadiene obtained decreased sharply, which is similar to those of conventional Ziegler-Natta catalysts. The microstructure of the product is not affected by the ratio of Cl/Nd and Al/Nd. The cis-1,4 content of polybutadiene is more than 98%. The rate of polymerization reaction is first order with respect to the concentration of monomer.Under the same experimental condition, the activity of the catalyst system, SAAC·Nd-Ph3CCl-Al(i-Bu)3, is higher than those of low molecule neodymium iso-octylate and naphthenate. This new catalyst system is also useful for the polymerization of isoprene, the cis-1,4 content of polyisoprene is about 96%. The activity of the catalyst system SMAC·Nd (styrene-methyl acrylic acid copolymer supported neodymium complex) is not as high as that of SAAC-Nd. The lower or higher content of neodymium in SAAC.Nd leads to the decrease of the catalytic ctivity.
基金
国家自然科学基金
