Abstract：
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.
摘要：
制备食品级三维（3D）打印材料的有效方法是使用高度浓缩的水包油乳液。这项研究报道了由食品级高内相Pickering乳液（HIPPE）构成的3D可打印材料，这些材料由ε-聚赖氨酸接枝的纤维素纳米纤维（ε-PL-TOCN）稳定。通过2,2,6,6-四甲基哌啶-N-氧基(TEMPO)-氧化纤维素(TOC)的ε-聚-1-赖氨酸接枝和连续机械处理制备ε-PL-TOCN。随后，化学结构,表征了ε-PL-TOCNs的微观结构和表面性能。结果表明,制备的ε-PL-TOCNs具有良好的分散性能,氨基带来的阳离子性能，和链结构的亲水/疏水功能，这证实了制备HIPPE的可行性。在0.8wt％的ε-PL-TOCN浓度和预乳化，然后连续进油，获得了内相体积分数为82％的HIPPE。HIPPE的储存稳定性，形态学,并进一步讨论了流变行为。成功制备了具有明显剪切稀化行为和高固体粘弹性的超稳定HIPPE，适用于3D打印。该工作拓展了纳米纤维素在乳液领域的应用,为制备食品级3D打印材料和多孔泡沫提供了新思路。
