In situ X-ray diffraction investigation of thermal decomposition of wood cellulose

Abstract

The kinetics of thermal decomposition of crystalline cellulose in spruce wood (Picea abies [L.] Karst.) was studied by in-situ X-ray diffraction using synchrotron radiation. Fiber diffraction patterns resulting from the crystal lattice of native cellulose arranged in oriented microfibrils were collected as a function of heat treatment time for various temperatures from 300 to 360°C. Sample heating was performed using a specially designed in-situ pyrolysis A c c e p t e d M a n u s c r i p t 2 meridional diffraction peaks. By quantitatively analyzing the kinetics for different temperatures it is found that thermal decomposition of crystalline cellulose in wood occurs mainly via a thermally activated decrease of the fibril diameter and an estimate for the activation energy is obtained. A simple scheme about the structural degradation of cellulose is presented.

Ultrastructural development of the softwood cell wall during pyrolysis

“…The lignin rich CML remained optically nearly unchanged (Figure 3b). c) From 2508C to 2758C: the crystallite size declines (Zickler et al 2007) and this is accompanied by an iso-orientation of the cellulose microfibrils (loosing their preferred orientation with a specific MFA) and the CML is also decomposed ( Figure 3c). d) 3008C: amorphisation of the cell wall proceeds to a disintegrated and fully random structure (Figure 3d).…”

“…Kim et al (2001) proposed first models on the thermally induced decomposition of cellulose microfibrils in wood including reduction of crystallinity (cellulose decomposition) along the fibre axis and rapid decomposition of individual microfibrils, while others are still intact. Recently, Zickler et al (2007) anticipated another model involving degradation starting from the equatorial surfaces of the cellulose crystallites, where initial decomposition should occur at the boundaries between the cellulose microfibrils and the polyoses. However, EM studies on wood treated at mild temperatures are scarce in the literature.…”

“…The resulting microfibril fragments have larger MFA. With increasing temperatures, the crystalline part of the cellulose is also degraded by various mechanisms (Zickler et al 2007) which finally leads to a complete loss of detectable orientation.…”

Characterization of Microcrystalline Cellulose after Pretreatment with Low Concentrations of Ionic Liquid-H2O for a Pyrolysis Process

“…Zickler et al (2007) also reported that the thermal decomposition of cellulose is mainly via a thermally activated decrease of the cellulose diameter. …”

Effect of Carbonization Time on the Morphology and Mechanical Properties of Natural Rubber Composites

“…Currently aerospace, automotive and construction applications employ Polymer-Fibre Composites systems with loading levels ranging from 15 to 65% weight of fibre reinforcements. This approach improves most mechanical properties [1][2][3][4][5] Biomass in fibre or particulate form has been used as reinforcing filler in polymeric composites materials. However, they present limitations such as moisture adsorption and low thermal stability [6,3].…”