Hydrogen bonds and polymerization in acrylamide under pressure


Correspondence to: Chitra Murli, High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India

Email: cmurli@barc.gov.in


Acrylamide (C3H5NO), a hydrogen-bonded amide, is an important compound from the point of view of basic and material research. It can be used as a model system for studying hydrogen bonding interactions in amides under pressure. As it is a monomer of polyacrylamide, an important polymer, high pressure investigation of polymerization in this material is also of interest. Our in-situ high pressure Raman spectroscopic investigations of acrylamide carried out up to 17 GPa under quasi-hydrostatic conditions indicate possible structural variations through the reconstruction of the N-H---O hydrogen bonds at pressures above 2.6 GPa. Emergence of several new spectral features at higher pressures indicate onset of polymerization. The characteristic polymer band becomes discernible at ~17 GPa. The increase in the relative intensity of the polymer peaks with respect to the monomer peaks on release to ambient conditions suggests that higher fraction of polymer is obtained on decompression. Copyright © 2013 John Wiley & Sons, Ltd.