SEPARATION AND IDENTIFICATION OF ETHYLENE-PROPYLENE BLOCK-COPOLYMER

In this paper, a commercial impact-resistant polypropylene alloy sampl e was fractionated with preparative temperature rising elution fractio nation (t.r.e.f.) technique and a series of ethylene-propylene block c opolymer fractions with different ethylene contents were obtained. Com bined with fractionation results, the block structure of them was iden tified with C-13 nuclear magnetic resonance (n.m.r.) spectroscopy and differential scanning calorimetry (d.s.c.). There are some transition segments between polyethylene and polypropylene segment in the block c opolymer. It was found that the number and kind of transition segments decreased with elution temperature, the length and melting temperatur e of polyethylene segment in block copolymer fractions showed a simila r tendency. (C) 1997 Elsevier Science Ltd.