用二苯醚改性钛系催化剂制备异戊橡胶

Preparation of isoprene rubber with titanium catalyst modified by diphenyl ether

用二苯醚改性钛系催化剂合成了异戊橡胶,讨论了催化剂各组分加料顺序对单体转化率、产物凝胶含量和相对分子质量的影响。结果表明,当催化剂三组分以等摩尔比加入时,所得产物主要为顺式结构,顺式摩尔分数约为95%。采用(三异丁基铝-二苯醚)-四氯化钛络合方式时,三异丁基铝/四氯化钛(摩尔比,下同)为0.8时活性最高。三组分单独加入反应体系时,二苯醚/三异丁基铝为0.4左右时转化率最高。用二苯醚的两种不同络合方式所得催化剂聚合产物的凝胶含量明显低于未添加二苯醚者,其中采用(三异丁基铝-二苯醚)-四氯化钛络合方式催化体系所得产物的特性黏数明显大于另外两种。

Isoprene rubber was prepared with titanium catalyst modified by diphenyl ether, and the effects of addition orders of various catalytic component on the monomer conversion, gel content and relative molecular mass were discussed in detail. It was found that the isoprene rubber with mole fraction of cis-unit 95% could be obtained if the catalyst component were added in equal mole ratio. For [Al （i-Bu）3-diphenyl ether]-TiCl4 system, the highest catalytic activity could be reached at the mole ratio of Al（i-Bu）3）/ TiCI4 of 0.8, but in the case of separate addition of the three components, the highest conversion could he ohtained at the mole ratio of diphenyl ether/Al（ i-Bu ）3 of 0. 4. The gel content of the isoprene ruhbers synthesized by the catalytic systems modified hy ethers were obviously reduced, and the intrinsic; viscosity of the polymer prepared by catalytic system [- AI（ i-Bu ）3-diphenyl ether]-TiCl4 was apparently higher than those of the other two systems.