Gel permeation chromatography (GPC) is a well-known method which is used for characterizing polymers according to their molecular weight distribution. The gel permeation chromatography analysis of engineering plastics at high temperatures needs specialized instruments and columns. The increased temperature is necessary across the entire experiment to inhibit re-crystallization and to keep the sample in solution.
How does Gel Permeation Chromatography Work?
Gel permeation chromatography instruments are made up of; a pump, to push the solvent through the instrument; an injection port, which introduces the test sample into the column; a column, to hold the stationary phase; one or more detectors, which detect the components as they exit the column; and software which controls the various elements of the instrument as well as calculating and displaying the results.
Although polymers are chains, when they are analyzed by gel permeation chromatography they typically behave like tiny spheres, with the size of the sphere depending on the molecular weight. Polymers with a higher molecular weight coil up to form larger spheres.
As components leave the gel permeation chromatography column, they are detected in numerous ways, and the elution behavior of the sample is shown in a graph, or chromatogram. The chromatogram displays the level of materials which have exited the column at any time, with the higher molecular weight, larger polymer coils eluting first, followed by successively lower molecular weight chains emerging later.
How is Gel Permeation Chromatography Used in Engineering Plastics?
Many recently developed types of engineering plastics display superior characteristics when put under high thermal or mechanical load. Such materials are designed to complement traditional materials like wood, metals or standard plastic. As the uses for these high-performance polymers increase, a need for methods which accurately and precisely characterize materials has arisen.
Engineering plastics like ultra-high molecular weight polyolefins or polyphenylene sulfides have a higher mechanical strength and resistance to physical degradation. These properties are generally favorable, however when in the context of characterization of polymers, they can cause an issue. Analysis is challenging due to the crystalline nature of the materials, often needing elevated temperatures or less common solvents for a complete dissolution.
Gel Permeation Chromatography Systems at RQM+ Lab Services
RQM+ Lab Services is at the forefront of gel permeation chromatography, with extensive facilities and the ability to operate a broad range of gel permeation chromatography systems, including standardized gel permeation chromatography, tetra detection gel permeation chromatography and high temperature gel permeation chromatography. We deploy multiple detection methods which include ultraviolet, refractive index, multi-angle light scattering (MALS) and viscometry.
At RQM+ Lab Services, we are also experts in the production of state-of-the-art polymeric media for gel permeation chromatography. Our gel permeation chromatography columns provide us the opportunity to apply multiple chemistries to the most complex method development projects. If you would like to find out more about our gel permeation chromatography solutions, contact us today.