AMPHOTERIC POLYAMIDOAMINES AS FUNCTIONAL SPECIALTY POLYMERS

This doctoral research centered on the synthesis and characterization of amphoteric polyamidoamines in both linear and cross-linked forms. The study is organized into two main thematic lines, each comprising multiple projects. The first one was to evaluate the potential environmental impact of amphoteric water-soluble PAAs, which may accidentally be released into ecosystems during or after their useful life. The ecotoxicity of PAAs was evaluated on the early stages of plant development using Lepidium sativum (watercress) seeds. In this study, the effectiveness and robustness of the seed germination test for assessing the phytotoxicity of water-soluble polymers has been investigated. Several parameters have been considered to assess the response of seeds exposed to PAA water solutions at different concentrations, including germination percentage, root and bud elongation. To extend the environmental toxicity assessment, the effects of PAAs were evaluated on aquatic ecosystems using zebrafish (Danio rerio) embryos, a vertebrate model organism sharing several features with mammals. Embryos development was monitored by performing the standard fish embryo acute toxicity test, evaluating the survival rate, morphological defects, organ deformities, and developmental delay compared to the control. The second thematic line aimed at exploring PAAs versatility in diverse applications, as water solutions and as hydrogels. Linear α-amino acid-derived PAAs with varying UV-absorption characteristics were investigated as functional coatings to enhance cotton photostability in accelerated photoaging tests under UVA-UVB irradiation. To gain deeper insight into this phenomenon, the photodegradation mechanism both in solution and in the solid state was investigated during the research period at the Université Clermont Auvergne. Photodegradation was evaluated under different experimental conditions, UVA and UVC irradiation, as well as in the presence of hydrogen peroxide as an oxidative agent. PAAs were investigated also in their cross-linked form through the development of biofunctional hydrogels. Cell-adhesive PAA-based composite hydrogels reinforced with electrospun poly-L-lactic acid mats, were studied as novel biomaterials with neuroregenerative and neuroprotective properties on preneuronal and immune cell lines.