Descriptif

Cette conférence est proposée par le professeur Sabu Thomas dans le cadre de sa cérémonie de remise de doctorat Honoris Causa et sera sous-titrée en français.

La chimie verte explore des méthodes respectueuses de l’environnement pour produire des nanoparticules issues de déchets agricoles, comme la cellulose, l’amidon, et la chitine, qui sont parmi les biopolymères les plus abondants. Ces nanoparticules, extraites via des traitements chimiques et mécaniques (broyage, alcalin, blanchiment, etc.), peuvent être fonctionnalisées pour devenir des biomatériaux intelligents et polyvalents. Elles sont utilisées dans des applications telles que les biocomposites, les filtres de purification d’eau, les échafaudages pour l’ingénierie tissulaire, et les pneus durables. Des techniques comme la microscopie électronique (TEM, SEM, AFM) et la spectroscopie infrarouge (FTIR) permettent d’étudier leur morphologie et leur structure. Ces matériaux renforcent les polymères biodégradables grâce à un réseau de liaison hydrogène. Valoriser ces biopolymères représente une solution écologique prometteuse pour répondre aux besoins croissants en matériaux durables et performants.

Présentation complète de Sabu Thomas (in English) :

Green chemistry started the search for benign methods for the development of nanoparticles from nature and their use in the field of biocomposite, antibacterial, antioxidant, and antitumor applications. Agro-wastes are eco-friendly starting materials to produce typical nanoparticles with well-defined chemical composition, size, and morphology. Cellulose, starch, chitin and chitosan are the most abundant biopolymers around the world.   All are under the polysaccharides family in which cellulose is one of the important structural components of the primary cell wall of plants.  Cellulose nanoparticles (fibers, crystals and whiskers) can be extracted from agro waste resources such as jute, coir, bamboo, pineapple leaves, coir etc. Chitin is the second most abundant biopolymer after cellulose, it is a characteristic component of the cell walls of fungi, the exoskeletons of arthropods and nanoparticles of chitin (fibers, whiskers) can be extracted from shrimp and crab shells. Chitosan is the derivative of chitin, prepared by the removal of acetyl group from chitin.  Starch nanoparticles can be extracted from tapioca and potato wastes. These nanoparticles can be converted into smart and functional biomaterials by functionalization through chemical modifications (esterification, etherification, TEMPO oxidation, carboxylation and hydroxylation etc) due to presence of large amounts of hydroxyl group on the surface. The preparation of these nanoparticles includes both a series of chemical as well as mechanical treatments; crushing, grinding, alkali, bleaching and acid treatments. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) are used to investigate the morphology of nanoscale biopolymers. Fourier transform infra-red spectroscopy (FTIR) and x-ray diffraction (XRD) are being used to study the functional group changes, crystallographic texture of nanoscale biopolymers respectively. Since large quantities of bio wastes are produced annually, further utilization of cellulose, starch and chitins as functionalized materials is very much desired. The cellulose, starch and chitin nanoparticles are currently obtained as aqueous suspensions which are used as reinforcing additives for high performance environment-friendly biodegradable polymer materials. These nanocomposites are being used as water purification filters, biomedical composites for drug/gene delivery, nano scaffolds in tissue engineering and high performance sustainable tire engineering.  The reinforcing effect of these nanoparticles results from the formation of a percolating network based on hydrogen bonding forces. The incorporation of these nano particles in several bio-based polymers have been discussed. The role of nano particle dispersion, distribution, interfacial adhesion and orientation on the properties of the ecofriendly bio nanocomposites will be carefully evaluated.

Cette conférence sera suivie d’une table ronde, Table ronde "Green nanomaterials and their polymer bio-nanocomposites: contribution to sustainable transition" en présence de :

• Professeur Sabu Thomas, Université Mahatma Gandhi, Inde
• Professeur Lorie Hamelin, Responsable de la Chaire INRAE "Sustainable Transitions towards low fossil Carbon Economies", INSA Toulouse
• Professeur Alain Dufresne, PAGORA - INP Grenoble
• Professeur Yves Grohens, Université de Bretagne Sud, Directeur de la plateforme ComposiTIC
• Professeur Ange Nzihou, IMT Mines Albi, Modérateur