Polyolefins: Determination of Molecular Weight and Branching Structure by GPC/SEC Polyethylene and Polypropylene are so-called Polyolefins. They are produced in large amounts every year. Depending on the process and catalyst used linear or branched polymers can be produced. In case of e. g. Polyethylene there are at least three polymer types: HDPE (High Density Polytheylene), LDPE (Low Density Polyethylene) and LLDPE (Linear Low Density Polytehylene). HDPE and LLDPE are made of linear or only slightly branched macromolecules with a high level of crystallinity. They form a dense structure in the final product. LDPE is made of highly branched molecules that form a final structure with low density due to a low degree of crystallinity....
Dynamic Light Scattering - an Important Tool for Protein Crystallography and Nanotechnology Dynamic Light Scattering (DLS) is an established technique in the field of protein crystallography. DLS is used to measure hydrodynamic sizes, polydispersities and aggregation effects of protein samples. These are important parameters for the crystallisation of proteins. DLS is also used in the nanotechnology research for the accurate and fast size measurement of nanoparticles made of different materials....
Do you see the complete picture? "Triple Detection" in Gel Permeation Chromatography Gel permeation chromatography (GPC) or also named size exclusion chromatography (SEC) is the most often used method for determining the molecular weight of natural and synthetic macromolecules. One specific strength of this method lies in the fact that by the separation process the whole molecular weight distribution is obtained. The molecular weight distribution contains much larger information for the characterization of polymer samples compared to a single value....
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