Influence of tructure on the properties of polypropylene copolymers and termopolymers

摘要

Several Ziegler-Natta copolymers of iPP with ethylene or 1-butene, and terpolymers with both counits\udhave been characterized, devoting special attention to the effect of composition and processing conditions\udon the crystal structure and final properties. DSC and X-ray diffraction were used to study the\udpolymorphism of copolymers and terpolymers. Comonomer insertion interrupts the isotactic sequences,\udacting as a structural defect, and the formation of g form is enhanced. Moreover, crystallinity decreases\udand crystal structure is modified. Comonomer type and concentration determine the extent of these\udmodifications, resulting in important changes in macroscopic properties. In particular, the excellent\udoptical properties of the analyzed terpolymers make them very attractive for applications such as\udtransparent film or packaging