Mitsuhiko Sakakibara

Modification of Neodymium High cis-1,4 Polybutadiene with Tin Compounds

High cis-1,4 polybutadiene was modified with tin compounds. The polymerization of 1,3-butadiene was carried out in the presence of a catalyst comprised of neodymium 2-ethylhexanoate, acetylacetone, triisobutyl- aluminum, diisobutylaluminum hydride and ethylaluminumsesqui chloride. The reactive polymer was then modified with triphenyltin chloride. Tin content increased with the increase in the number of molecules. This increase can also be seen by GPC measurement with RI and UV dual detectors; that is, the inten sity of UV absorbance at the low molecular weight region was higher than that at the high molecular weight region. From these results, this polymer was thought to be modified by tin com pounds at the chain terminal end. The abrasion characteristics of the modified polymer were measured with a Pico abrasion tester and were found to be improved.

25. Modification of High cis-1, 4 Polybutadiene by Neodymiun Catalyst

High cis-1,4 polybutadiene was modified with tin compound. The polymerization of 1,3-butadiene was carried out in the presence of a catalyst comprised of (a) neodymium 2-ethylhexanoate, (b) triisobutyl aluminium, (c) diiso-butyl aluminium hydride, (d) ethylaluminiumsesqui chloride and (e) acetylacetone. The reactive polymer was then modified with triphenyltin chloride. The polybutadiene prepared as described above showed high cis -1, 4 structure content and broad molecular weight distribution. The tin content increased with decrease in the molecular weight of the polybutadiene. This means that the tin content increased with the increase in the numbers of molecules. This can be also seen by GPC measurement with RI and UV dual detectors: that is, the intensity of UV absorbance at the low molecular weight region was higher than that at the high molecular weight region. From these results, this polymer is thought to be modified by tin compound at the chain terminal end.