A stereo block poly(1-butene) was synthesized with η5-pentamethylcyclopentadienyltribenzyl-oxidetitanium(Cp*Ti(OBz)3) and modified methylaluminoxane(MAO) as catalyst.The original polymer was extracted successively by boiling ether and heptane

and each fraction was characterized by 13C-NMR

WAXD and DSC. It was found that ether soluble fraction was atactic poly(1 butene)

heptane solube fraction was stereo block poly(1-butene)

and heptane insoluble fraction was isotactic one. The isotacticity

glass transition temperature and crystallinity of the polymers soluble in boiling heptane were increased with decreasing polymerization temperature.At lower polymerization temperature (30℃ and 0℃)

the polymers with the degree of crystallinity over 30% had two melting peake which were 43℃/55℃ and 85℃/88℃

respectively.But at higher temperature (40℃) noncrystalline polymer obtained from heptane-solube fraction was characterized by WAXD and DSC.The relationship between the propagation mechanism and the microstructure of the prepared products was studied by 13C-NMR. It was indicated that the 1

2-insertion was easier than 2

1-insertion.