Fast and solvent free polymerization of carbohydrates induced by non-thermal atmospheric plasma

Abstract

Non-thermal atmospheric plasma (NTAP) is a physical technology that has been previously employed for surface treatment (cleaning, coating, erosion, etc.) and water or air depollution. We show here that, beyond surface effects, NTAP is capable of enabling the complete and fast polymerization of various mono- and disaccharides in the solid state within only a few minutes and at low temperature (40-80 [degree]C). NTAP-induced polymerization involves a radical mechanism and yields water soluble polysaccharides with a mean molar mass of up to 100 000 g mol-1 and a mean hydrodynamic radius of 3 nm. Although polymerization reactions promoted by NTAP occurs in a random manner, the [small alpha]-1,6 and [small beta]-1,6 linkages are however dominant. Furthermore, we discovered that NTAP is highly selective, strongly favoring glycosylation over other chemical transformations in the bulk. Under our working conditions, glycosyl units are preserved that constitute the repeating units of the polysaccharide product. No chemical degradation (e.g. intramolecular dehydration reactions) was observed, allowing a white powder to be recovered with a yield higher than 93 wt%. From a practical point of view, NTAP has great potential for breakthrough in the production of polysaccharides, notably because it does not require the use of a solvent or catalyst, thus by-passing the traditional post-treatment of aqueous effluents and catalyst recycling characteristic of biotechnological polysaccharide production. Its efficiency at low temperature also prevents carbohydrates from degradation. Finally, NTAP proceeds on an on/off switch basis, allowing the polymerization reaction to be started and stopped quasi instantaneously

Impact of Nonthermal Atmospheric Plasma on the Structure of Cellulose: Access to Soluble Branched Glucans

“…During this "water-poor phase",a n equilibriumw as reached that probablyi nvolves competitive depolymerization/repolymerizationr eactions as well as 1,6-anhydrization of reducing units, which is further supported by our previous report on the polymerization of mono-a nd disaccharide induced by NTAP. [17] Tentative mechanism…”

Microbubble-enhanced dielectric barrier discharge pretreatment of microcrystalline cellulose

“…Whilst treatment with APP has shown to depolymerise cellulose structure through cleavage of the hydrogen bonds, random repolymerisation reactions have also been reported [ 39 ]. Delaux et al found that mono- and disaccharides subjected to DBD plasma starts to polymerise when the reactor temperature reaches 40 °C [ 40 ]. DBD plasma is a source of heat and the liquid temperature could rise gradually exceeding 40 °C locally near the membrane leading to repolymerisation.…”

The Pivotal Role of Catalysis in France: Selected Examples of Recent Advances and Future Prospects.

“…This transformation occurred selectively within minutes at a temperature below 70 °C and led to a large library of soluble branched glucans with a controlled degree of polymerization. Mono‐ and disaccharides were also quasi instantaneously polymerized by atmospheric plasma, thus widening the library of poly‐ or oligosaccharides that can be synthesized using this technology …”