Effect of the Brazilian thermal modification process on the chemical composition of Eucalyptus grandis juvenile wood: Part 1: Cell wall polymers and extractives contents

Abstract

This article reports the first study of the influence of the Brazilian process of thermal modification called VAP HolzSysteme ® on the chemical composition of Eucalyptus wood. Flatsawn boards of Eucalyptus grandis juvenile wood were tested for four treatment levels: untreated and thermally modified at final cycle temperatures of 140, 160 and 180 °C. Chemical analyses were carried out according to the standards of the Technical Association of the Pulp and Paper Industry and encompassed total extractives, insoluble lignin, holocellulose (cellulose + hemicelluloses) and solvent soluble extractives in water (cold and hot) and ethanol:toluene (1:2 v.v.) mixture. The chemical composition of thermally modified Eucalyptus grandis juvenile wood was significantly changed by the VAP HolzSysteme ® process compared to untreated wood. Only the wood thermally modified at final cycle temperature of 180 °C was significantly different for all the chemical analyses performed compared to untreated wood.

Infrared spectroscopy of the surface of thermally-modified teak juvenile wood

“…A relative increase in lignin content was observed after thermal modification to both heartwood and sapwood (Table 2). These results agree with those of other authors (Poubel et al 2013, de Moura et al 2012, Batista et al 2016, Yalcin and Sahin 2015. Thermally-modified heartwood had an increase of 45% and 63% in relative lignin content for 180ºC and 200ºC, respectively, whereas in thermally-modified sapwood, they increased approximately 1.7% and 5.1%.…”

Chemical characterization and ftir spectroscopy of thermally compressed eucalyptus wood panels

“…; only a relatively small decrease in the yields of α-cellulose was observed when compared to the decrease in holocellulose yields. The findings obtained from this study are supported by a study of Batista et al (2016a). Table 4.…”

“…Total lignin percentages, yields of holocellulose and amount of α-cellulose in the samples were compiled in Table 4. The yields of holocellulose in the control sample was determined as 71,5 while this value was 69,4 for Eucalyptus grandis wood (Batista et al 2016a). The holocellulose content of S3 sample was decreased significantly because due to their amorphous and branched polymeric structure especially hemicelluloses are less stable against the effect of the thermal degradation when compared to the other polymeric wood constituents (i.e., lignin and cellulose) (Fengel and Wegener 1984).…”

Biological resistance of heat-treated wood of Pinus caribaea and Eucalyptus saligna

“…Regarding the chemical composition of wood, Batista et al (2016), studying the thermal treatment of eucalyptus at 140, 160, and 180 °C, verified that the chemical composition of the Eucalyptus grandis juvenile wood was significantly altered by the heating process. Studies indicate that heat-treatment causes, fundamentally, the partial degradation of hemicellulose (Brito et al 2006, Brito et al 2008, Garcia et al 2012.…”