Structural characterization of Argania spinosa Moroccan wooden artifacts during natural degradation progress using infrared spectroscopy (ATR-FTIR) and X-Ray diffraction (XRD)

authors

• Abdellatif Boukir
• Somia Fellak
• Doumenq Pierre

document type

abstract

The present work is focused on spectroscopic study of four samples of Argan wooden artifact pertaining to the 17 th , 18 th , 20 th and 21 st centuries. The objective is to characterize their unknown structures by the study of their non degraded parts and to investigate changes occurred in their degraded parts due to the natural degradation process. Attenuated total reflectance Fourier transform infrared spectroscopy gauges the presence of many functional groups related to cellulose I and/or II (OH, CO -C and-CH 2), hemicelluloses (particularly C¼O acetoxy ester band at 1732 cm À1), and lignin (OH phenolic, C ar-O and C¼C ar) and provides qualitative information on the state of wood alteration by informing on the evolution of new former C¼O bands. The degree of conversion to carbonyl group, especially quinone or p-quinone at 1650 cm À1 , is correlated to lignin degradation, while the absence of the C¼O acetoxy absorption is ascribable to occurred deterioration in hemicelluloses, and partial degradation of cellulose with enhancement of the C¼O region between 1730-1630 cm À1. X-ray diffraction determines the presence of two forms of cellulose; amorphous cellulose at 18.5 2θ and predominant crystalline cellulose I β at 2θ ¼ 22.6 which characterized by an intense peak. The decrease of crystallinity index values confirms the deterioration level and obvious changes in crystallinity level. However, the microcrystalline structure appears unaltered because no significant changes were observed for calculated cristallite seize. The obtained results depend on the prolonged time of ageing, natural deterioration phenomena, and wood part (internal or external) that is exposed to degradation. The combination of these two methods is useful for an accurate estimation of the degradation level of argan wood.

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