Social event to take place from 12:30pm-12:45pm in the breezeway.
Abstract:
Chitin, the second most abundant biopolymer after cellulose, is present in the shell of crustaceans, in the cuticle of insect and even in some fungi.1 It can be converted into chitosan, a highly praised material with application as a fertilizer, water treatment flocculant, biomedical fibers and food additive. Yet today's technologies for chitin extraction and chitosan production rely on the use of corrosive treatments, high energy input and large quantities of by product effluents. Herein I am presenting my group's effort to tackle this question, through the use of solvent-free methods, and the road map we have established to access several exciting added-value polymers and nanomaterials. Mechanochemistry is becoming an established method for the sustainable, solid-phase synthesis of scores of nanomaterials and molecules, ranging from active pharmaceutical ingredients to materials for cleantech.2 Beyond its ability to trigger reactivity through energy delivery to chemical systems, mechanochemistry is also a way to activate precursors and mix reagents that may react further in a subsequent aging phase.3 We showed that mechanochemistry and aging could be used effectively for the deacetylation of chitin using solid NaOH as reagent.4 This process yielded high molecular weight chitosan with minimal use of energy and solvent. We have also explored the possibility to reduce the molecular weight of chitosan via mechanochemical and aging-based acid treatment.6 Moving upstream, we have explored the extraction of chitin from crustacean shells, and demonstrated effective extraction of high quality chitin using milling with various solid acids.5 Chitin, like cellulose, is a crystalline material, granting access to nanocrystals via acid or oxidative partial hydrolysis.1 Classic methods being water and chemical intensive, we have developed a mechanochemical version, in which aging done under high humidity in a shaker was needed to afford high yields of excellent quality chitin nanocrystals.7 This method can be extended to cellulose nanocrystals synthesis. Finally, we have also extended the use of mechanochemistry to the fabrication of chitosan nanocrystals from chitin nanocrystals.8 We developed hydrogels from chitosan and chitin nanocrystals, with exceptional gelling properties and demonstrated their applicability for slow drug release.
Figure 1. Chitin and chitosan derivates accessed from crustacean shells by mechanochemistry.
1. T. Jin, T. Liu, E. Lam, A. Moores, Nanoscale Horiz. 2021, 6, 505-542
2. J.-L. Do, T. Friščić, ACS Cent. Sci. 2017, 3, 1, 13–19
3. M. J. Cliffe, C. Mottillo, R.S. Stein, D.-K. Bučar, T. Friščić, Chem. Sci., 2012, 3, 2495-2500
4. T. Di Nardo, C. Hadad, A. Nguyen Van Nhien, A. Moores, Green Chem. 2019, 21, 3276-3285
5. F. Hajiali, J. L. Vidal, T. Jin, L. de la Garza, M. Santos, G. Yang, A. Moores, ACS Sustainable Chem. Eng. 2022, 10, 34, 11348–11357.
6. G. Yang, E. Lam, A. Moores, ACS Sustainable Chem. Eng. 2023 11 (20), 7765-7774
7. T. Jin, T. Liu, F. Hajiali, M. Santos, Y. Liu, D. Kurdyla. S. Regnier, S. Hrapovich, E. Lam, A. Moores, Angew. Chem. Int. Ed. 2022, 61 (42), e202207206
8. T. Jin, T. Liu, S. Jiang, V. Michaelis, D. Kurdyla, B.A. Klein, E. Lam, J. Li, A. Moores, Green Chem. 2021, 23, 6527-6537