Wednesday, February 24
Characterization of copolymers with carbonyl groups and other polyolefin applications by high temperature GPC-IR
ON DEMAND Analytical Characterization
Wednesday, February 24
2:00 pm - 4:00 pm



Characterization of copolymers with carbonyl groups and other polyolefin
applications by high temperature GPC-IR
E. López, A. Ortín, F.Samper, B. Monrabal
The full characterization of polyolefins requires a high-temperature GPC/SEC analysis
to be made with specific detectors. The infrared (IR) has been extensively used as
concentration and chemical composition detector to obtain the molar mass
distribution and short chain branching information or comonomer content in ethylene-
-olefin and in ethylene propylene copolymers (1- 2). However, other types of
copolymers, such the important class of vinyl acetate, or chemical groups as the
carbonyl group generated in oxidative degradation processes, show absorption bands
beyond the CH stretching band in MID-IR for which existing IR detection methods were
available so far.
Recently a high-performance filter-based IR detector with broad spectral range has
been introduced which can detect the typical C=O absorption in the 1740 cm -1 band
with high sensitivity, which allows its application coupled to standard HT-GPC. The new
IR6 is an evolution of the proven IR5 detector, in which some of the optoelectronics
components have been modified to extend the spectral range up to the carbonyl band
and beyond. The number of available bands simultaneously detected has also been
increased up to six, which opens the way to development of new specialized
The present work is focused on assessing satisfactory response of the carbonyl band
detection by analyzing a series of ethylene vinyl acetate copolymers with different
comonomer content (7.5% to 40% weight) and ethylene butyl acrylate. Other polymers
with different carbonyl groups from the mentioned above have been also studied to
check the response in the band of 1740 cm-1, although a broad spectral range with
custom filters is also available which allow the detection of absorbance from different
chemical groups.
Degraded/aged polyolefins and recycled materials are also a type of products suitable
to be characterized by HT-GPC-IR, which opens a new application field for that
carbonyl band detection. Besides having the molar mass distribution, thanks to this
new enhanced infrared detector, the carbonyl content can be measured in the same
analysis adding that valuable composition information to the study of these products.
The last application studied is the determination/quantification of additives in
polypropylene. Thanks to the carbonyl band the presence of a specific additive can be
clearly confirmed, which would help to the process control of additive, as well as
studying its preservation during material processing steps.
(1) Journal of Chromatography A. Volume 1257, 2012, Pages 66-73. Filter-based infrared detectors
for high-temperature size exclusion chromatography analysis of polyolefins. Alberto Ortin, E.
Lopez, B. Monrabal, J. R. Torres-Lapasio, M. C. Garcia-Alvarez-Coque.
(2) ICPC 2012.Macromolecular Symposia. Volume 330, 2013, Pages 63-80. Characterization of
Chemical Composition along the Molar Mass Distribution in Polyolefin Copolymers by GPC

Using a Modern Filter-Based IR Detector. A. Ortín, J. Montesinos, E. López, P. del Hierro, B.
Monrabal, J.R. Torres-Lapasió, M.C. García-Álvarez-Coque.

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