The properties of polymers are affected by the polymer chain length / mass, therefore it is important to be able to accurately determine this during synthesis / the manufacturing process. 

While there’s a number of methods which can do this, performing diffusion measurements by NMR spectroscopy is one of the most powerful and flexible. Using the pulsed-field gradients, available as standard on the X-Pulse Broadband Benchtop NMR Spectrometer, the diffusion constant of polymers can be determined. Since diffusion constants correlate to the size of a molecule, and hence its mass, an appropriate calibration allows the molecular mass / chain length to be determined. 

In this Application Note, measurement of polymer masses is demonstrated using a series of samples of polyethylene glycol (PEG).

By downloading this application note you will learn:

• The important of knowing the chain length / mass of polymers
• How to measure polymer chain length / mass by NMR spectroscopy 
• One of the uses of pulsed-field gradients on a NMR spectrometer

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