 |
|
|
|
|
|
|
Article 1 - 5 of 7 |
|
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....
|
|
|
|
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....
|
|
Half a Century of Chromatography with Agilent and Predecessors
One Century of Chromatography with Twsett (1903)
Twsett originated the chromatography with his work about the separation of chlorophyll in 1903. For some time it was relatively quite around this new technology. Exceptions were the workings of Kuhn and Lederer (1931) as well as of Hesse (1936 and 1942). A break through succeeded to E. Cremer during the 40ies, but hardly considered caused by the war events, what however in the years 1950/51 by the conception of the gas chromatography suddenly changed and involved a rapid development...
|
|
SRI Gaschromatographs: "Customized GC" since 1986
Since 1986 SRI Instruments Inc. (Las Vegas) develops gas chromatography systems with the main objective to build an instrument which can easily be adapted to the customer's needs. The result was a modular built GC which can be equipped with up to six different detectors to cover a wide range of analytical methods...
|
|
|
|
|
|
|
|
Top
