Electronic Structure and Ground State Properties of PMMA Polymer: II. Protection of PMMA Against Gamma Irradiation Damage

ABSTRACT

The equilibrium ground state geometric parameters of N,N,N′,N′,-tetraoxaloylsulphanilamide (Ligand I), N,N-dioxaloylbenzenesulpony-N′,N′,-dioxaloylthiocarbazide (Ligand II) and p-N,N-dioxaloylaminobenzene-N′,N′-dioxaloylbenzenesulphonyloxamide (Ligand III) as polyfunctional ligands were investigated theoretically using AM1-MO method. The expected biradicals formed after gamma radiolysis for each ligand can be detected. The radiation protection of the PMMA matrix from gamma rays, using the biradicals formed of ligands (I), (II), and (III), can be considered theoretically. The structure of the protected chains formed after recombination of two symmetric chains with biradical are theoretically modelled, because in the reaction medium the chain of PMMA formed is asymmetric. All interpretations concerning the ground state properties of the protected chains are qualitative. The thionyl, phenyl, and benzenesulphonyl biradicals are more efficient than carbonyl, thioamides, and sulphonyl biradicals as indicated from the MO-results, molecular weight investigation, and infrared spectroscopy. The protection of PMMA by the formed biradicals is confrmed by proton NMR spectroscopy.

Keywords:

• biradicals groups
• protection mechanism
• Sulphanilamide
• AM1-MO calculations
• PMMA

Acknowledgments