Characterization of microcrystalline cellulose extracted from walnut and apricots shells by alkaline treatment

Abstract

In this study, microcrystalline cellulose (MCC) was isolated from walnut and apricot shells (WS and AS) as agricultural wastes in order to use it as reinforcement in polymer composites. The microcrystalline cellulose was extracted by alkaline treatment and bleached by peroxide as an environmentally friendly treatment, called walnut cellulose (WC) and apricot cellulose (AC). The chemical composition of the samples was set according to the Technical Association of Pulp and Paper Industry (TAPP). After treatments, the alpha-cellulose content increased by about 23 % for the two used cellulose sources. The structural and morphological properties of the samples were investigated by Fourier transform infrared spectroscopy in the attenuated total reflectance mode (ATR-FTIR), optical microscopy (OM), X-ray diffraction and scanning electron microscopy (SEM). The crystallinity index values evaluated for WC and AC via X-ray diffraction were respectively 86.4 and 80.3 %. The alkaline soluble fractions of walnut (ASW) and apricot (ASA) shells were recovered and characterized by OM and ATR-FTIR spectroscopy. Furthermore, their chemical composition was analyzed. The characterization and the properties of the WC and AC were similar to those of commercial MCC and MCC prepared in literature from wood and some agricultural wastes.

Optimization of the Rheological Properties of Self-Assembled Tripeptide/Alginate/Cellulose Hydrogels for 3D Printing

“…ATR-FTIR spectroscopy was employed to study the chemical structure of the inks ( Figure 7 a). In the region of 4000–2000 cm −1 , two bands common to all polysaccharides appeared, a broad band at 3260 cm −1 due to the O–H stretching vibrations, and a peak at 2926 cm −1 was attributed to the C–H stretching vibrations [ 50 ]. To obtain a better insight into the specific signals of every component of the ink, the region oof 1760–400 cm −1 was analyzed in detail ( Figure 7 b).…”

“…The small peak at 1372 cm −1 (peak 7) was due to the CH deformation and the band at 1160 cm −1 corresponded to the C–O–C asymmetric stretch vibrations (peak 8) [ 52 , 53 ]. A last peak appeared at 1058 cm −1 (peak 9) due to the stretching mode of the C–O–C bonds [ 50 , 54 ].…”

Impact of microcrystalline cellulose extracted from walnut and apricots shells on the biodegradability of Poly (lactic acid)

“…PLA (Nature Works 2002D) (MFI = 6.18 g/10 min, density = 1.23, Tg = 63 °C, Tm = 154 °C, Mw = 215,000, Mw/Mn = 1.9 and D-isomer = 4.2%) was used (Bouti et al, 2022). WC and AC microcrystalline cellulose (particle size ≤40 μm, holocellulose content was 85.0 et 87.0% and crystallinity index was 86.4 and 80.3% for WC and AC, respectively) used in this work are extracted from apricots and walnut shells according alkaline treatment and peroxide bleaching (Mahmoud et al, 2021). Chloroform (99.9%) was supplied by Biochem.…”

“…The isolation of cellulose fibers requires the removal of other components and several treatments were developed to recover these constituents at different forms: microfiber cellulose (Moo-Tun et al, 2020), nanofiber cellulose (Frone et al, 2013), cellulose fiber, microcrystalline cellulose (Mahmoud et al, 2021) and nano-crystalline cellulose (El Achaby et al, 2018). The final physico-chemical properties of cellulose depend on its treatment method, the origin and the initial composition of the raw material (biomass).…”

“…In the present paper, a valorization of the microcrystalline cellulose extracted from walnut shells and apricot shells (WC and AC) reported in a previous work (Mahmoud et al, 2021) was done in order to elaborate PLA composites using cast solution.…”