A blog on polymer analysis and all things related
To complement the main discussion on calibration and data interpretation in the article introduction to GPC/SEC, this additional section provides deeper practical guidance for analysts who routinely operate GPC/SEC systems in research, production, or quality environments. It expands on the . . . read more »
Gel Permeation Chromatography (GPC) is a fundamental technique for determining the molecular weight distribution of polymers. However, not all materials require the same analytical conditions. Polyolefins, for instance, must be analyzed at High Temperature (HT) to achieve complete dissolution, as do certain high-performance engineering polymers such as PPS, PEEK, and others that also demand elevated temperatures and specific solvents. In contrast, polymers such as polystyrene, PMMA, copolymers, and resins are . . . read more »
As sustainability goals push the plastics industry toward greener processes, solvent-free Intrinsic Viscosity (IV) testing – based on melt-flow analysis – has gained attention. Such methods promise fast, eco-friendly testing with results equivalent to solvent-based IV methods. But are the results truly equivalent in all scenarios? And is the process genuinely faster when everything is considered? Melt-flow based IV testing certainly has its place. In this article, we break . . . read more »
In the field of polyolefin characterization, Gel Permeation Chromatography (GPC) remains the gold standard for evaluating molecular weight distribution (MWD) and resin performance. And just as important as selecting the appropriate characterization technique for your resin, is choosing the right instrument for the job. Polymer Char offers two distinct GPC solutions to meet different laboratory needs: GPC-IR and GPC-QC. While both instruments are built on the same reliable chromatographic foundation, . . . read more »
Polyolefin copolymer resins incorporate comonomers such as 1-butene, 1-hexene, or 1-octene, which results in short-chain branches irregularly added that influence the crystallinity and final density of the resin. Depending on their density, the resulting resins are classified as high-density polyethylene (HDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), and very low-density polyethylene (VLDPE). In the case of linear low-density polyethylene (LLDPE), the incorporation of the comonomer in the . . . read more »
The simultaneous analysis of concentration and chemical composition in Gel Permeation Chromatography (GPC) or Size Exclusion Chromatography (SEC) is of significant interest for today’s complex polyolefin copolymers. In polyethylene and copolymers, chemical composition is centered around the study of short-chain branches, created by the incorporation of comonomers into the main chain. The measurement of short-chain branching adds a new dimension to the conventional GPC/SEC technique that may be critical . . . read more »
Polyolefins with heterogeneous chemical composition are becoming prevalent in the industry. These resins are produced by incorporating comonomers into the main chain in order to reduce their crystallinity and extend the range of product performance. To define these copolymers, characterization by molar mass (the most popular characterization technique) will not tell us about the intermolecular distribution of comonomer into the linear chains. Instead, we need to find out about . . . read more »
Polyolefin resins have become complex polymers by design, achieved with multi-reactor processes and the incorporation of comonomers that improve their performance for the desired application. This design complexity requires advanced methods of analysis, as the average properties measured by melt index and density techniques are not enough to define the microstructure of these polymers. Size Exclusion Chromatography (SEC) – also called Gel Permeation Chromatography (GPC) – offers a great . . . read more »
This guide covers some practical considerations regarding solvent, analysis conditions, and laboratory supplies needed for analyzing polyolefins by Gel Permeation Chromatography (GPC) or Size Exclusion Chromatography (SEC) technique. The data and recommendations presented here have been derived from the day-to-day operation of the and instruments in . Solvent Consumption and Analysis Time In Gel Permeation Chromatography, solvent consumption and analysis time depend mainly on the vial . . . read more »
High Temperature Size Exclusion Chromatography (SEC) – also called Gel Permeation Chromatography (GPC) – is the most widespread technique to characterize the microstructure of polymers. Different detector-configurations can be used with SEC instrumentation, each of them contributing to the resin’s characterization in a different manner. In this guide we will cover the industry’s most used detectors for the characterization of polyolefins by SEC/GPC technique: two types of concentration detectors . . . read more »
By coupling GPC-IR and GPC-QC* with any of Polymer Char’s Infrared detectors – IR4, IR5, or IR6 – it is possible to obtain both molecular weight distribution and chemical composition information of polyolefin resins. Each IR detector was developed with a specific application in mind, and their capabilities vary from one another. The purpose of this guide is to help you choose the Infrared detector most suited to your . . . read more »
Preparative fractionation systems, like PREP mc2 and PREP C20, fractionate polymers by dissolving them in the appropriate solvent and then separating their molecules according to certain parameters, such as molecular weight and crystallinity. At the end of the process in the preparative system, the resulting polymer fractions are still mixed with the solvent, so we need to remove the solvent in order to obtain the dry polymer for each fraction. . . . read more »
As analysts in the Gel Permeation Chromatography (GPC) field, we know that picking the right columns and developing a stable analysis method is essential to delivering precise and accurate results. Even the most comprehensive analytical system will fail to provide the quality of data required if the columns perform a poor separation or if the analytical process is not stable. GPC columns are at the core of GPC . . . read more »