Biorefinery Processes Research Group, Chemical & Environmental Engineering Department, Faculty of Engineering, Gipuzkoa, University of the Basque Country UPV/EHU, Plaza Europa 1, 20018 Donostia, Spain.
University of Pau and the Adour Region, E2S UPPA, CNRS, Institute of Analytical and Physicochemi-cal Sciences for the Environment and Materials (IPREM-UMR 5254), 371 Rue du Ruisseau, 40004 Mont de Marsan, France.
Molecules. 2021 Mar 4;26(5):1371. doi: 10.3390/molecules26051371.
Cellulose and lignocellulose nanofibrils were extracted from pistachio shells utilizing environmentally friendly pulping and totally chlorine-free bleaching. The extracted nanofibers were used to elaborate nanopaper, a continuous film made by gravimetric entanglement of the nanofibers and hot-pressed to enhance intramolecular bonding. The elaborated nanopapers were analyzed through their mechanical, optical, and surface properties to evaluate the influence of non-cellulosic macromolecules on the final properties of the nanopaper. Results have shown that the presence of lignin augmented the viscoelastic properties of the nanopapers by ≈25% compared with fully bleached nanopaper; moreover, the hydrophobicity of the lignocellulose nanopaper was achieved, as the surface free energy was diminished from 62.65 to 32.45 mNm with an almost non-polar component and a water contact angle of 93.52°. On the other hand, the presence of lignin had an apparent visual effect on the color of the nanopapers, with a ΔE of 51.33 and a ΔL of -44.91, meaning a substantial darkening of the film. However, in terms of ultraviolet transmittance, the presence of lignin resulted in a practically nonexistent transmission in the UV spectra, with low transmittance in the visible wavelengths. In general, the presence of lignin resulted in the enhancement of selected properties which are desirable for packaging materials, which makes pistachio shell nano-lignocellulose an attractive option for this field.
从开心果壳中提取纤维素和木质素纳米纤维，利用环保制浆和全无氯漂白。提取的纳米纤维用于制备纳米纸，这是一种通过纳米纤维的重力缠结和热压制备的连续薄膜，以增强分子内键合。对所制备的纳米纸进行机械、光学和表面性能分析，以评估非纤维素大分子对纳米纸最终性能的影响。结果表明，与完全漂白的纳米纸相比，木质素的存在使纳米纸的粘弹性提高了约 25%；此外，木质纤维素纳米纸具有疏水性，表面自由能从 62.65 降低到 32.45 mNm，几乎为非极性组分，水接触角为 93.52°。另一方面，木质素的存在对纳米纸的颜色有明显的视觉影响，ΔE 为 51.33，ΔL 为-44.91，这意味着薄膜明显变暗。然而，就紫外透过率而言，木质素的存在导致在紫外光谱中几乎没有透过，在可见光波长下透过率较低。总的来说，木质素的存在增强了某些性能，这些性能是包装材料所需要的，这使得开心果壳纳米木质素纤维素成为该领域的一个有吸引力的选择。
