X-ray diffraction on aged Brazilian wood species

Highlights: • There is strong interdependence between crystallinity percentage and crystallite size of wood. • There is interdependence between crystallinities by diffractogram area and the Segal method. • Natural weathering provoked increase of crystallinity of in-natura wood evaluated using XRD. • Wood density is not closely linked with the crystallinity and crystallite size. -- Abstract: Characterization of wood is important for best performances. X-ray diffraction (XRD) is a non-destructive technique that has been used for determination of crystallinity and crystallite size of isolated cellulose samples and samples of wood under some treatment. Determining weathering effects on material properties is important for their outdoor uses, mainly exposed to ultraviolet radiation. This paper aims to evaluate changes in crystallinity and crystallite size of Brazilian wood, covering all Brazilian code strength classes (ABNT NBR 7190:1997), exposed to artificial and natural weathering. In this context, XRD is considered a new, fast and non-destructive alternative to improve the wood characterization. Results showed no significant changes of wood for artificial aging. On the other hand, natural aging presented increase of crystallinity and crystallite size of 9.16% and 9.93%, respectively, in 360 days of exposure. According to our results, it is possible to conclude that XRD is effective in evaluating wood microstructure.