Characterization of γ-radiation induced polymerization in ethyl methacrylate and methyl acrylate monomers solutions. (December 2017)

• Record Type: Journal Article
• Authors: Baccaro, Stefania; Casieri, Cinzia; Cemmi, Alessia; Chiarini, Marco; D'Aiuto, Virginia; Tortora, Mariagrazia
• Is Part Of: Radiation physics and chemistry. Volume 141(2017)
• Page Start: 131
• Page End: 137
• Publication Date: 2017-12
• Subjects: EMA/MA co-polymerization -- Polymerization by gamma radiation -- ATR-FTIR -- 1H NMR -- 13C NMR -- DOSY-NMR -- Paraloid B72; Radiation chemistry -- Periodicals; Radiometry -- Periodicals; Radiation -- Periodicals; Chimie sous rayonnement -- Périodiques; 539.2
• DOI: 10.1016/j.radphyschem.2017.06.017
• Languages: English
• ISSNs: 0969-806X

Abstract

Abstract: The present work is focused on the γ-radiation induced polymerization of ethyl methacrylate (EMA) and methyl acrylate (MA) monomers mixture to obtain a co-polymer with specific features. The effect of the irradiation parameters (radiation absorbed dose, dose rate) and of the environmental atmosphere on the features of the final products was investigated. Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Nuclear Magnetic Resonance high-resolution analyses of hydrogen and carbon nuclei ( 1 H and 13 C NMR) were applied to follow the γ-induced modifications by monitoring the co-polymerization process and allowed the irradiation parameters optimization. Diffusion-Ordered NMR (DOSY-NMR) data were used to evaluate the co-polymers polydispersity and polymerization degree. Since the last parameter is strongly influenced by the γ radiation and environmental conditions, a comparison among samples prepared and irradiated in air and under nitrogen atmosphere was carried out. In presence of oxygen, higher radiation was required to obtain a full solid co-polymer since a partial amount of energy released to the samples was involved in competitive processes, i.e. oxygen-containing free radicals formation and primary radicals recombination. Irrespectively to the environmental atmosphere, more homogeneous samples in term of polymerization degree dispersion was achieved at lower dose rates. At radiation absorbed doses higher than those needed for the formation of the co-polymer, while in case of samples irradiated in air heavy depolymerization was verified, a sensible increase of the samples stability was attained if the irradiation was performed under nitrogen atmosphere. Highlights: EMA/MA co-polymer was successfully obtained by γ-induced polymerization. Solvent-free EMA/MA monomers mixture was used as starting material. Irradiation parameters and environmental atmosphere influence the final co-polymer. More stable co-polymers were produced under nitrogen atmosphere.