Structure and Mechanical Properties of Ethylene/1-Octene Multiblock Copolymers from Chain Shuttling Technology

Abstract

The mechanical properties and the structural transformations occurring during deformation of some commercial grades of ethylene/1-octene multiblock copolymers (OBCs) obtained from chain shuttling technology are analyzed. The samples are characterized by a statistical multiblock architecture, where soft and amorphous blocks with high octene concentration (≈18.9 mol %) alternate with hard and crystalline blocks with low octene concentration (≈0.5 mol %). The length of blocks (BL) and the number of blocks/chain (NB) change from chain to chain according to a statistical distribution. The selected samples have molecular mass in the range 85–130 kg/mol, percentage of hard segments in the range 15–27%, and a melting temperature of ≈120 °C. The average molecular masses of the hard blocks MH and soft blocks MS are in the ranges 2–3 kg/mol and 6–15 kg/mol, respectively, whereas the number of blocks/chain is in between 2 and 17. Even though the samples are characterized by similar octene concentration, small differe...