STUDY OF CRYOSTRUCTURIZATION OF POLYMER SYSTEMS .10. H-1-NMR AND H-2-NMR STUDIES OF THE FORMATION OF CROSS-LINKED POLYACRYLAMIDE CRYOGELS

Some features of the formation of polyacrylamide cryogels have been studied by means of H-1- and H-2-NMR. These gels were prepared by free radical copolymerization of acrylamide and N,N'-methylene-bis-acrylamide in a frozen aqueous medium. Using the spectral changes during polymerization, the cryotropic gelation may be conventionally subdivided into three stages during which the narrow NMR signals due to the low molecular weight components disappear, while the broad signals attributed to the formation of the polymeric compound develop. It was demonstrated that the dynamics of polymerization depend on the freezing procedure, i.e. on the thermal prehistory of a sample.