The all‐polymer composites and blends made of ethylene–octene copolymer and partially disentangled polypropylene using a new processing approach

Abstract

All‐polymer composites and blends of ethylene–octene copolymer (EOC) and polypropylene (PP) were produced in the extrusion process. They had the same composition (96:4 wt.%), but five different entanglement densities of PP macromolecules. Depending on the processing temperature, below or above the melting point of PP, fibers or spherical inclusions were formed inside the EOC matrix. The production of PP fibers directly during mixing was possible by reducing the entanglement of macromolecules in this polymer. During fiber formation by solid‐state plastic deformation, the crystallinity of PP decreased, especially for the less entangled polymers. The presence of fibers influenced the mechanical properties of the composites, which were different from those of the blends. Both in blends and composites, the matrix was reinforced, but in the composites the effect was stronger and the measured stresses increased with the lower degree of PP entanglement. SAXS and microscopic observations showed that cavitation occurred in the deformed composites. All‐polymer composites, in which the reinforcement was created as a result of polymer deformation with limited entanglements, have properties that are advantageously different from traditional ones, which opens the prospect of their application.