Publications by authors named "Matthieu Fumagalli"
We prepared chitosan (CHI) hydrogels reinforced with highly charged cellulose nanofibrils (CNF) by the desalting method. To this end, the screening of electrostatic interactions between CHI polycation and CNF polyanion was performed by adding NaCl at 0.4 mol/L to the chitosan acetate solution and to the cellulose nanofibrils suspension.
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- Researchers developed rubber materials using a diene elastomer and tailored nanocellulose fillers, achieving better mechanical reinforcement.
- The nanocellulose was derived from freeze-dried cellulose nanocrystals and microfibrillated cellulose with high specific surface areas, modified for better compatibility with the rubber matrix.
- Enhanced materials showed significant modulus increases and maintained flexibility; in some cases, the stress-stiffening behavior resulted in ultimate stress increases of up to 7 times compared to the unfilled matrix.
Supramolecular polymer networks have been designed on the basis of a π-electron donor/acceptor complex: naphthalene (N)/cyclobis(paraquat-p-phenylene) (CBPQT = B). For this purpose, a copolymer of N,N-dimethylacrylamide P(DMA-N1), lightly decorated with 1 mol% of naphthalene pendant groups, has been studied in semi-dilute un-entangled solution in the presence of di-CBPQT (BB) crosslinker type molecules. While calorimetric experiments demonstrate the quantitative binding between N and B groups up to 60 °C, the introduction of BB crosslinkers into the polymer solution gives rise to gel formation above the overlap concentration.
View Article and Find Full Text PDFMost polymeric thermoresponsive hydrogels contract upon heating beyond the lower critical solution temperature (LCST) of the polymers used. Herein, we report a supramolecular hydrogel system that shows the opposite temperature dependence. When the non-thermosesponsive hydrogel NaphtGel, containing dialkoxynaphthalene guest molecules, becomes complexed with the tetra cationic macrocyclic host CBPQT , swelling occurred as a result of host-guest complex formation leading to charge repulsion between the host units, as well as an osmotic contribution of chloride counter-ions embedded in the network.
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- Aqueous suspensions of microfibrillated cellulose were processed and freeze-dried to create highly porous aerogels with a surface area of 100 m²/g.
- The aerogels underwent gas-phase esterification with palmitoyl chloride, leading to a variety of cellulose palmitates with degrees of substitution (DS) ranging from 0 to 2.36.
- The low DS samples (0.1-0.4) showed that the cellulose microfibrils were hydrophobic and esterified only on their surface, maintaining their inner structure.