SYNTHESIS OF POLYPROPENE-BLOCK-POLY(ETHYLENE-CO-PROPENE) BY SHORT-PERIOD POLYMERIZATION WITH MGCL2-SUPPORTED ZIEGLER CATALYST

The short-period polymerization method was successfully applied to the synthesis of a novel diblock copolymer, polypropene-block-poly(ethyle ne-co-propene). The polymerization was carried out for ca. 0,1 s with a MgCl2-supported Ziegler catalyst. The copolymers obtained showed uni modal curves in gel-permeation chromatography without any peak in the low-molecular-weight region. After extraction with heptane, the fracti on of poly(ethylene-co-propene) remained unchanged in the copolymer bu t disappeared in a commercial so-called block-type copolymer. All the results suggest the formation of polypropene-block-poly(ethylene-co-pr opene), in which poly(ethylene-co-propene) is chemically linked with p olypropene.