STUDYING OF POLYELECTROLYTE COMPLEXES OF SODIUM ALGINATE WITH POLYETHYLENEIMINE BY PYROLYTIC MASS SPECTROMETRY METHOD

Abstract

Polyelectrolyte complexes (PECs) based on sodium alginate (SA) with polyethyleneimine (PEI) were synthesized at a molar ratio of SA:PEI = 1.00:0.25 (PEC-1) and SA:PEI = 1.0:0.5 (PEC-2). The temperature intervals of thermodegradation for both the initial components and PECs were determined by pyrolytic mass spectrometry. It was shown that the molar ratio in these PECs significantly affects their swelling level in an aqueous environment as well as their mechanical characteristics. For instance, PEC-2 film is stiffer and more brittle compared to PEC-1 film, which retains flexibility. It has been revealed that PEC-2 exhibits a lower total ionic current of volatile components and a smaller number of ionic fragments generated during pyrolysis across the entire temperature range compared to PEC-1. In other words, PEC-2 is more resistant to temperature impact than PEC-1, which can be attributed to the difference in the molecular structure of the PECs. The formation of a greater number of ionic and hydrogen bonds in PEC-2, in our opinion, results in the formation of a stiffer and more ordered structure (compared to PEC-1). It is worth noting that the composition of PEC-2 is closer to stoichiometric, which leads to a decrease in the swelling degree of its film in water, and a decrease in its elasticity.