School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195, USA.
School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195, USA.
Int J Biol Macromol. 2024 Jan;254(Pt 1):127487. doi: 10.1016/j.ijbiomac.2023.127487. Epub 2023 Oct 19.
Lignin is a common and abundant byproduct of the pulp and paper industry and is generally burned to produce steam. Opportunities exist to acquire greater value from lignin by leveraging the properties of this highly conjugated biomacromolecule for applications in UV absorption and polymer reinforcement. These applications can be commercialized by producing value-added lignin nanoparticles (LNPs) using a scalable sonochemical process. In the present research, monodisperse LNPs have been synthesized by subjecting aqueous dispersions of alkali lignin to acoustic irradiation. The resulting particle size distribution and colloidal stability, as determined by dynamic light scattering, transmission electron microscopy and zeta potential analysis, of LNPs can be adjusted by varying the solution pH and ultrasonication energy. As-synthesized LNPs with a mean diameter of 204 nm were incorporated into poly (vinyl) alcohol (PVA) to prepare thin and flexible nanocomposite films using a simple solvent casting method. The addition of 2.5 wt% LNP increased the material's Sun Protection Factor up to 26 compared to 0 for neat PVA, while maintaining light transmission above 75 % in the visible spectra. In addition, the tensile strength and elastic modulus of the PVA nanocomposites improved by 47 % and 36 %, respectively. The presence of LNP also enhanced the thermal stability of the materials. Significantly, the proposed sonochemical process may be generally applicable to the synthesis of a range of naturally-derived LNPs for a variety of value-added applications.
木质素是制浆造纸工业的常见且丰富的副产品，通常被燃烧以产生蒸汽。通过利用这种高度共轭的生物大分子的特性，将木质素用于紫外线吸收和聚合物增强等应用，可以从木质素中获得更高的价值。通过使用可扩展的超声化学工艺生产增值木质素纳米颗粒 (LNP)，可以实现这些应用的商业化。在本研究中，通过对碱木质素的水相分散体进行声辐射，合成了单分散的 LNP。通过动态光散射、透射电子显微镜和zeta 电位分析确定的 LNP 的粒径分布和胶体稳定性，可以通过改变溶液 pH 值和超声能量来调节。用简单的溶剂浇铸法将平均直径为 204nm 的合成 LNP 掺入聚乙烯醇 (PVA) 中，制备出薄而柔韧的纳米复合材料薄膜。与纯 PVA 的 0 相比，添加 2.5wt% 的 LNP 将材料的防晒系数提高到 26，同时可见光范围内的透光率保持在 75%以上。此外，PVA 纳米复合材料的拉伸强度和弹性模量分别提高了 47%和 36%。LNP 的存在还提高了材料的热稳定性。值得注意的是，所提出的超声化学工艺可能广泛适用于一系列天然衍生的 LNP 的合成，以用于各种增值应用。
