Size Exclusion chromatography branched polymers

Characterization of Branched Polymers by Size Exclusion Chromatography with Light Scattering Detection... 

Styring, M. G., Armonas, J. E., and Hamielec, A. E., An experimental evaluation of a new commercial viscometric detector for size-exclusion chromatography (SEC) using linear and branched polymers, /. Liq. Chromatogr, 10, 783, 1987. 

Mourey, T. H. and Coll, H., Size exclusion chromatography with two-angle laser light-scattering (SEC-TALLS) of high-molecular-weight and branched polymers, /. Appl. Polym. Sci., 56, 65, 1995. 

Yu, L.P. and Rollings, J. E., Quantitative branching of linear and branched polysaccharide mixtures by size exclusion chromatography and on-line low-angle laser light-scattering detection, /. Appl. Polym. Sci., 35, 1085, 1988. 

A viscosity online detector in a size exclusion chromatography (SEC) instrument allows for a universal calibration for polymers with known K- and a-values. For polymers that are only soluble at high temperature, e.g., polyolefines, high-temperature detectors are available, which can be operated up to 200°C. In addition to molar mass measurements, viscosity detectors have also been employed successfully to obtain structural information of branched polymers [28]. 

A combination of infrared spectroscopy with size exclusion chromatography has a wide application range in the characterization of copolymers, adhesives, impurity profiling in polymers and branching in polyolefines [60-65]. Commonly, the solvent used as a mobile phase absorbs strongly in the... 

Branched polymers are often analyzed by means of size exclusion chromatography (SEC). It should always be kept in mind that fractionation in SEC is on the basis of the hydrodynamic volume, i.e. [41], Analysis based on a mass... 

The architecture of hypeibranched polymers and dendrimers is connected with difficulties in determining molar mass. Many of the common characterization techniques—e.g. size exclusion chromatography (SEC)—used for polymers are relative methods where polymer standards of known molar mass and dispersity are needed for calibration. Highly branched polymers exhibit a different relationship between molar mass and hydrodynamic radius than their linear counterparts. 

Yu, L. -P, Rollangs, J. E. (1987). Low-angle laser light scattering-aqueous size exclusion chromatography of polysaccharides molecular weight distribution and polymer branching determination. Journal of Applied Polymer Science, 33, 1909-1921. 

A wide variety of polymers have been analyzed by gel-permeation, or size-exclusion, chromatography (sec) to determine molecular weight distribution of the polymer and additives (86—92). Some work has been completed on expanding this technique to determine branching in certain polymers (93). Combinations of sec with pyrolysis—gc systems have been used to show that the relative composition of polystyrene or acrylonitrile—polystyrene copolymer is independent of molecule size (94). Improvements in gpc include smaller cross-linked polystyrene beads having narrow particle size distributions, which allow higher column efficiency and new families of porous hydrophilic gels to be used for aqueous gpc (95). 

Gel Permeation Chromatography (GPC), also known as Size Exclusion Chromatography (SEC), is a technique used to determine the average molecular weight distribution of a polymer sample. Using the appropriate detectors and analysis procedure it is also possible to obtain qualitative information on long chain branching or determine the composition distribution of copolymers. 

Size exclusion chromatography is the premier polymer characterization method for determining molar mass distributions. In SEC, the separation mechanism is based on molecular hydrodynamic volume. For homopolymers, condensation polymers and strictly alternating copolymers, there is a correspondence between elution volume and molar mass. Thus, chemically similar polymer standards of known molar mass can be used for calibration. However, for SEC of random and block copolymers and branched polymers, no simple correspondence exists between elution volume and molar mass because of the possible compositional heterogeneity of these materials. As a result, molar mass calibration with polymer standards can introduce a considerable amount of error. To address this problem, selective detection techniques have to be combined with SEC separation. 

Between 1950 and 1960 Size Exclusion Chromatography (SEC) became a popular technique in two branches the fractionation of synthetic polymers, described as gel permeation chromatography, and in the resolution of biopolymers, termed as gelfil-tration. The former was performed on cross-linked porous synthetic polymers, the latter on cross-linked polysaccharides (Sephadex). 

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