High-Performance GPC and SEC

Some workers nsed SEC for the first fractionation, and TLC [2,3] and high-performance precipitation liqnid chromatography [4, 5] were applied as the second chromatographic method. Balke and Patel [6,7] performed cross-fractionation by orthogonal chromatography (SEC-SEC) in which different mobile phases were used. Tanaka and co-workers [8] used the 

Methods other than GPC that have been used to measure MWD of polymers include osmosis methods, viscosity methods, light scattering methods, ultracentrifugation, precipitation fractionation and column fractionation, and others, but these methods are complicated, and in some cases lengthy in operation. 

since a polymer is a mixture of molecules differing in molecular weight, the value of a measurement obtained by such methods is nothing but a statistical mean value assuming 

Polymethyl methacrylate Sensitivity as an electron resist Increases with M and narrow MWD 

Polystyrene Solution viscosity and shear stability index Decreases with a decrease of caused by shearing 

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