Several diesters were developed as internal donors of the Ziegler-Natta catalysts

the molecular structures of the diesters are close to that of diisobutyl phthalate.Furthermore

the effects on the performance of the catalysts were studied.Results showed that the catalysts prepared by different preparation processes have the same MgCl2 lattice style ().The changing of diesters have notable influences on the porosity and the specific surface areas of the catalysts

and the polymerization performance and the PP isotactic index vary with different addition ways of the diesters in the preparation processes of the catalysts. When the internal donor is diisobutyl cis-cyclohexane dicarboxylate

the polymerization activity of the catalyst and the PP index are the highest

reaching the level of the industry catalyst. In the polymerization of CAT-2A

using CMMS as the external electron donor

the ratio of Si to Ti is 10 and the ratio of Al to Ti is 100

the polymerization activity and PP isotactic index reach the highest level.