Crystallization Behavior and Mechanical Properties of Regiodefective, Highly Stereoregular Isotactic Polypropylene: Effect of Regiodefects versus Stereodefects and Influence of the Molecular Mass

摘要: Highly isotactic polypropylene samples, containing a very low amount of rr stereodefects (0.1−0.2%) and slightly higher concentration defects regioregularity (0.8−0.9% 2,1 erythro units), with different molecular masses have been prepared an isospecific but not fully regioselective metallocene catalyst. The effects the presence regiodefects effect mass on mechanical properties crystallization behavior analyzed. Samples are stiff much more fragile than samples only stereodefects. defects, even for concentrations, produces instead increase ductility improvement drawability at room temperature. stereo- is probably related to their levels inclusion inside crystalline phase. uniform in crystals makes stereodefective regioregula...