Radiation-Induced High-Temperature Conversion of Cellulose

Abstract

Thermal decomposition of cellulose can be upgraded by means of an electron-beam irradiation to produce valuable organic products via chain mechanisms. The samples being irradiated decompose effectively at temperatures below the threshold of pyrolysis inception. Cellulose decomposition resembles local "explosion" of the glucopyranose unit when fast elimination of carbon dioxide and water precede formation of residual carbonyl or carboxyl compounds. The dry distillation being performed during an irradiation gives a liquid condensate where furfural and its derivatives are dominant components. Excessively fast heating is adverse, as it results in a decrease of the yield of key organic products because pyrolysis predominates over the radiolytic-controlled decomposition of feedstock. Most likely, conversion of cellulose starts via radiolytic formation of macroradicals do not conform with each other, resulting in instability of the macroradical. As a consequence, glucosidic bond cleavage, elimination of light fragments (water, carbon oxides, formaldehyde, etc.) and formation of furfural take place.

Radiation-induced modifications in natural fibres and their biocomposites: Opportunities for controlled physico-chemical modification pathways?

“…Moreover, the presence of oxygen during irradiation enhances cellulose degradation, probably due to the reaction of oxygen with radicals formed at the atom C-5 that induces the AGU ring cleavage (Arthur, 1971). While not changing the degradation processes, temperature also have a significant effect on the decomposition yield of cellulose, especially above 100°C, because it favours the transfer of radicals formed upon irradiation to neighbouring cellulose chains (Ponomarev and Ershov, 2014).…”

“…This results in the release of gaseous products such as water, hydrogen, carbon monoxide and carbon dioxide. The subsequent oxidative degradation of cellulose leads to the formation of carbonyl groups (C]O) and carboxyl groups (COOH) in cellulose substrates, especially in open air and high temperature conditions (Arthur, 1971;Ponomarev and Ershov, 2014). Based on FTIR experiments, it has been shown that the relative absorbance of the band related to carbonyl groups (∼1740 cm −1 ) increases linearly with the radiation dose for gamma irradiated cotton fibres (Takács et al, 2000).…”

Valuable Food Molecules with Potential Benefits for Human Health

“…Radiation processing of natural polymers has received much less attention over the years because most of the natural polymers undergo chain scission reaction when exposed to high-energy radiation and because of the difficulty in processing natural polymers in various forms and sizes [211]. There have been many reports about the effects of gamma irradiation on the degradation of polysaccharides, including the treatments of chitosan [211], cellulose [212], β-glucan [213], and so on. Gamma irradiation improved the solubility and decreased the viscosity of β-glucan by the radiolysis of the glycosidic bonds, and this effect was dependent upon the absorbed dose.…”

Tailoring Pulp Cellulose with Electron Beam Irradiation: Effects of Lignin and Hemicellulose

“…In lignocellulosic materials, the underlying radiolysis mechanism of EBI is based on the ability of ionizing irradiation to form cellulose radicals that can decompose following scission of the glycosidic bond. 6,7 Compared to conventional chemical methods for controlling cellulose molecular mass, EBI offers a number of advantages. It is completely chemical-free and can be applied in-line anytime in the process prior to dissolution.…”