CHROMATOGRAPHY 51
Improving polyolefin analysis by gel permeation chromatography
How to set a higher standard in gel permeation chromatography analysis.
The GPC-IR is setting new standards for gel permeation chromatography.
P
Fig. 1. Sequential injections of SRM 1475 linear polyethylene (x2) and SRM 1476 branched polyethylene (x2) at 150ºC in 1,2,4-trichlorobenzene, injection volume 200µL, concentration 0.9mg/ml. A low molar mass hydrocarbon is added to every injection as flow rate marker.
olyolefin (PO) is the largest volume industrial polymer in the world. It is
used to produce a wide range of commercial products that touch nearly every aspect of our daily lives; such as car parts, pipes, packaging films and so on.
Polyolefin products derive their broad range of end-use properties from their semi- crystalline structure. Te ability to incorporate comonomers in Polyethylene (PE) and Polypropylene (PP) makes it possible to control the polymer crystallinity, and thus control the rigidity and flexibility of polyolefin products. Te
controlling factor also depends to a great extent on the comonomer variations across the molar mass distribution (MMD). In today’s competitive marketplace products are targeted to specific applications by tailoring both MMD and comonomer incorporation. Tis requires a reliable and fast analytical tool for studying comonomer incorporation or chemical composition along the MMD in all kinds of polyolefins.
Te high-temperature GPC-IR by Polymer Char is a compact and fully automated instrument that is setting a new standard in gel permeation chromatography
(GPC) for polyolefins, and is becoming the preferred choice in the industry.
Optimum detection Te IR detector has been shown to be the most appropriate detector for gel permeation chromatography of polyolefins. Flow rate, temperature and pressure variations have little influence on the IR absorbance, and so an excellent baseline stability is delivered by this detector (Fig. 1). In addition, IR shows no injection peaks and the chromatograms are easily integrated, resulting in reliable and precise molar mass averages. What makes the IR detector
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