Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China.
Int J Biol Macromol. 2023 Jul 31;244:125142. doi: 10.1016/j.ijbiomac.2023.125142. Epub 2023 May 29.
An effective method for preparing food-grade three-dimensional (3D) printing materials was the use of highly concentrated oil-in-water emulsions. This research reported 3D printable materials constructed from food-grade high internal phase Pickering emulsions (HIPPEs) that were stabilized by ε-poly-l-lysine grafted cellulose nanofiber (ε-PL-TOCNs). The ε-PL-TOCNs were prepared via ε-poly-l-lysine grafting of 2, 2, 6, 6-tetramethylpiperidine-N-oxyl (TEMPO)-oxidized cellulose (TOC) and the successive mechanical treatment. Subsequently, the chemical structure, microstructure and surface properties of ε-PL-TOCNs were characterized. The results showed that the prepared ε-PL-TOCNs had excellent dispersion performances, cationic properties brought by amino groups, and hydrophilic/hydrophobic functions of chain structure, which confirmed the feasibility of preparing HIPPEs. The HIPPEs with an internal phase volume fraction of 82 % were obtained at 0.8 wt% ε-PL-TOCNs concentration and pre-emulsification followed by continuous oil feeding. The HIPPEs' storage stability, morphology, and rheological behavior were further discussed. The ultra stable HIPPEs with apparent shear-thinning behavior and high solid viscoelasticity were successful produced, which was suitable for 3D printing. This work expanded the application of nanocellulose in emulsions field and provided a new thinking to prepare food-grade 3D printable materials and porous foam.
一种制备食品级三维（3D）打印材料的有效方法是使用高浓度的油包水乳状液。本研究报道了由食品级高内相Pickering 乳状液（HIPPEs）构建的 3D 可打印材料，该乳状液由 ε-聚赖氨酸接枝纤维素纳米纤维（ε-PL-TOCNs）稳定。ε-PL-TOCNs 通过 2,2,6,6-四甲基哌啶-N-氧自由基（TEMPO）氧化纤维素（TOC）的 ε-聚赖氨酸接枝和连续的机械处理制备。随后，对 ε-PL-TOCNs 的化学结构、微观结构和表面性质进行了表征。结果表明，所制备的 ε-PL-TOCNs 具有良好的分散性能、氨基带来的阳离子特性以及链结构的亲水性/疏水性功能，证实了制备 HIPPEs 的可行性。在 0.8wt%ε-PL-TOCNs 浓度下，通过预乳化和连续加油，可以获得内相体积分数为 82%的 HIPPEs。进一步讨论了 HIPPEs 的储存稳定性、形态和流变行为。成功制备了具有明显剪切变稀行为和高固体粘弹性的超稳定 HIPPEs，适用于 3D 打印。这项工作扩展了纳米纤维素在乳液领域的应用，并为制备食品级 3D 可打印材料和多孔泡沫提供了新的思路。
