Séminaires

Articles

• Séminaire SIMM - Nathan Ferrandin Schoffel (SIMM)

  13 février
  Jeudi 7 mars de 14h00 à 15h30 - Charpak

  Nathan Ferrandin Schoffel (SIMM)
  Aminosilanes as a one-pot treatment for simultaneous deacidification and strengthening of heritage papers

  Acidity is a major issue in the preservation of paper-based collections. A large number of paper documents of mediocre quality produced in the late 19th and early 20th century are very acidic and brittle, their public access hence being drastically restricted. To find a solution for these documents, treatments based on copolymerized aminoalkylalkoxysilanes (AAASs), which allow simultaneous deacidification and mechanical strengthening of paper, have been developed at Centre de Recherche sur la Conservation (CRC) and Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI). As these treatments showed efficacy for some papers but not for others, the results had to be better understood before a possible use by the conservation professionals.
  My PhD project (2017-2021) advanced the understanding of the interactions/reactions between AAASs and the cellulosic substrate, with a better identification of the parameters that reduce the treatment efficacy. To that purpose, AAAS treatments were applied to newsprint lignocellulosic papers of complex compositions, and NMR and FTIR were used to characterize the physicochemical bonds formed in-situ. In conjunction, the evolution of the physicochemical properties (pH, optical and mechanical properties) of a large range of papers treated several years ago were studied. Finally, several options for optimized formulations of the AAAS treatments were tested, including the use of reducing and deacidifying agents as pre-treatments for paper and thermal post-treatment sequences.

• DEMI JOURNEE SCIENTIFIQUE SIMM

  29 novembre 2023
  Lundi 18 décembre 2023 de 08h00 à 13h00 - Holweck

• Séminaire SIMM - Oscar Lopez-Pamies (Illinois)

  29 novembre 2023
  Mercredi 13 décembre 2023 de 11h00 à 12h30 - Holweck

  Oscar Lopez-Pamies (University of Illinois Urbana-Champaign)
  Towards a Complete Theory of Fracture : The Special Case of Rubber

  In this talk, I will present a macroscopic (continuum) theory, alongside its numerical implementation, aimed at describing and predicting when and how fracture nucleates and propagates in a body made of rubber that is subjected to arbitrary quasistatic loading conditions.

  I will begin by summarizing the slew of existing experimental observations on nucleation and propagation of fracture in rubber that have been generated ever since vulcanized rubber was invented by Charles Goodyear in the 1840s. The observations will reveal that there are three basic ingredients that any attempt at a complete macroscopic theory of fracture ought to account for : i) the elasticity of the rubber, ii) its strength at large, and iii) its fracture energy.

  Having pinpointed the basic ingredients required for a complete theory, I will then present one such theory, regularized, of phase-field type. The theory can be viewed as a natural generalization of the phase-field approximation of the celebrated variational theory of brittle fracture of Francfort and Marigo (1998) — which is nothing more than the mathematical statement of Griffith's competition of bulk and fracture energies — to account for the material strength at large.

  In the latter part of the presentation, I will illustrate the descriptive and predictive capabilities of the theory via simulations of several famous experiments, including poker-chip experiments in both natural and synthetic rubber.

• SEMINAIRE SIMM/C3M - Martina Stenzel (UNSW, CAMD, Sydney)

  29 novembre 2023
  Vendredi 8 décembre 2023 de 11h00 à 12h30 - Holweck

  Martina Stenzel (UNSW, CAMD, Sydney)

  Sugar coated nanoparticles big and small – how polymer science can enhance nanomedicine

  Nanomedicine is a field of interesting interest. Rapid development of nanotechnology has allowed the incorporation of multiple therapeutic, sensing and targeting agents into nanoparticles. Most commercially available nanoparticles use poly(ethylene glycol) PEG as hydrophilic coatings. However, materials based on sugars such as polymers with pendant carbohydrates, coined glycopolymers, are attractive alternatives. Carbohydrates play a pivotal role in many biological processes and by using glycopolymers we mimic naturally occurring events. The presence of carbohydrates on the surface on nanoparticles can therefore help the uptake of these nanoparticles into mammalian cells. In this presentation, we look into a range of nanoparticles based on glycopolymers, ranging from ultrasmall nanometer sizes nanoparticles to large micron-sized 2D platelets and discuss how these particles can be used in drug delivery applications. A focus will be how small molecules such as drugs can be loaded and how the drugs change the properties of polymers, and thus their biological activity.

• Séminaire SIMM

  10 novembre 2023
  Jeudi 16 novembre 2023 de 14h00 à 15h00 - Holweck