Presented at Pittcon Conference & Expo, 2011. Atlanta, GA, USA.
Benjamín Monrabal, Alberto Ortín, Pilar del Hierro, Juan Sancho-Tello. Polymer Char, Valencia, Spain.
Characterization of polyolefins in terms of composition is carried out by techniques such as TREF, CRYSTAF, and CEF where polymers are fractionated by crystallizability, which is controlled by tacticity or by the level of Short-chain Branching (SCB). Those techniques, although very powerful, are limited to semicrystalline polymers and do not provide a separation of the components in the amorphous fractions which are often present in industrial polyolefins.
The use of high temperature HPLC in various modes has been investigated in the last years for the analysis of polyolefins. Separation of polypropylene and polyethylene by isocratic HPLC has been achieved using two solvents on a silica based column, and by solvent gradient HPLC. The use of carbon-based columns provided full separation of polypropylene by tacticity and improved resolution of olefin copolymers which could also be analyzed in a two-dimensional approach (HPLC x GPC).
In this poster we introduce the developments in instrumentation and software to perform high temperature HPLC in isocratic, solvent gradient, and temperature gradient mode, as well as the possibility to perform high temperature HPLC x GPC using an Infrared detector.