Calibration for polymers

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]. 

WAXS calibration for polymer materials can be simplified if one considers the fact that polymers are chain molecules. This means that for wide scattering angles in... 

Like most analytical techniques, the measurements employed in ThFFF are sensitive to temperature. The most critical temperature to control in ThFFF is the cold wall temperature. By controlling that temperature, the preparation of universal calibration plots is simple and straightforward. Once such plots are obtained, they can be apphed to all ThFFF instruments with adequate control of the cold wall temperature. Without precise temperature control, universal calibration plots can still be obtained, but this involves a tedious procedure for each polymer-solvent system under consideration. The incorporation of cold wall temperature in ThFFF calibrations for polymer analysis is well described in the entry ThFFF Molecular Weight and Molecular Weight Distributions. 

Thus, the concept of universal calibration also provides an appropriate calibration for polymers for which no calibration standards exist... 

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