高反式1,4-聚异戊二烯合成的新方法

A NEW METHOD OF SYNTHESES OF HIGH TRANS-1,4- POLYISOPRENE

反1,4-链节含量接近100％的聚异戊二烯（TPI）具有天然杜仲胶或古塔胶的结构和性能,结晶熔点60—65℃,被认为是作为形状记忆功能材料,如医用矫形材料、各种温敏变形材料的最理想聚合物。关于TPI的合成路线,国外报道主要有V体系（VCl3/AlEt3及其负载改性型）和V-Ti混合体系(VCl3/β-TiCl3/AlEt3和Ti（OR）4/

A kind of high trans-1,4-polyisoprene (TPI) was synthesized by coordinative polymerization of isoprene with supported titanium catalyst and triisobutylaluminium. The experimental results illustrated that the catalytic efficiency (CE) increases when the monomer concentration, polymerization temperature and time are increased. Under suitable conditions the CE can-exceed 2000 gTPI/gTi and the inherent viscocity of the TPI is about 4-6dl/g. The micro-structure of the synthesized TPI was characterized by IR and 13C-NMR spectra It was verified that the microstructure of the TPI is nearly all trans-1,4 chain unit(above 99%). Its melting temperature is about 60℃ by DSC method.