Crystallization Elution Fractionation: measure the Chemical Composition

The introduction of single site catalysts and multiple reactor technology allows the design of new Polyolefin resins with improved properties for each particular application, and the Chemical Composition Distribution (CCD) has become the most discriminating microstructure parameter in these polymers. The proper analysis of the CCD necessarily requires a fractionation process, typically done according to crystallizability; existing analytical techniques like Temperature Rising Elution Fractionation TREF 1 and Crystallization Analysis Fractionation CRYSTAF 2-4 have shown in the last years to be of great value in the polyolefins industry. Although analytical time has been reduced to a few hours per sample in both CRYSTAF and TREF, a faster method without sacrificing resolution was required, which ended in the development of a new technique known as Crystallization Elution Fractionation (CEF) .