Crystallization behavior of polybutene‐1 in the anisotropic system blended with polypropylene

Abstract

AbstractDevelopment of supermolecular structure in drawn polypropylene (PP)/polybutene‐1 (PB‐1) blends was studied. PP (matrix)/PB‐1 (70/30) blend films were drawn and heat‐treated at fixed length or free ends at temperatures above the melting point of PB‐1. It was found that a long axis of the PB‐1 lamella is aligned perpendicular to the draw direction, and the c‐axis of the PB‐1 crystal is oriented perpendicular both to the draw direction and the plane of the surface of the blend film. Drawn, then heat‐treated PP/PB‐1 blend films gave a SAX pattern having a cross type scattering maximum on the meridian. It was confirmed that vertical scattering originates from the PB‐1 crystal developed during melt recrystallization. It was proposed that the structural development of PB‐1 in drawn PP/PB‐1 film can be explained on the basis of transcrystallization of PB‐1 in the confined 2‐dimensional space in the PP matrix. The kinetics of isothermal crystallization of PB‐1 was examined by use of a DSC technique. The result supports the conclusion that the heterogeneous nucleation of PB‐1 followed by 2‐dimensional crystal growth prevailed in oriented PP/PB‐1 blend film.