Polyaniline nanofibers as a new gamma radiation stabilizer agent for PMMA

Abstract

Polyanilines are reported to exhibit stabilizing effects in rubber mixtures submitted to gamma-irradiation and thermo-oxidative treatment. Such abilities may be explained by their action as radical scavengers. Since radical formation followed by main chain scission is a widely accepted mechanism for radiolytic degradation of PMMA, polyaniline is a promising additive for commercial plastics submitted to radiosterilization processing. In this work, we investigated the ability of polyaniline emeraldine salt nanofibers (PANF-HCl) in preventing radiation damage on PMMA matrix. Effects of gamma-irradiation on PMMA/PANF-HCl composites films were assessed by comparison of the variation of viscosityaverage molar mass (Mv) of PMMA at 25 kGy dose when compared to commercial PMMA films. Samples containing 0.15% PANF-HCl (wt/wt) retained 92% of the initial Mv after irradiation while control sample presented 42% of Mv retention. When exposed to 60-200 kGy doses, PANF-HCl embedded into PMMA matrix preserved their oxidation state but started to exhibit mild deprotonation. PANF-HCl nanofibers were characterized by Diffuse Reflection Infrared Fourier Transform Spectroscopy (DRIFTS) and Scanning Electronic Microscopy (SEM). PMMA/PANF-HCl composites films were characterized by SEM and UV-VIS spectroscopy.