Mugnaini Giulia, Resta Claudio, Poggi Giovanna, Bonini Massimo
CSGI & Department of Chemistry "Ugo Schiff", via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy.
CSGI & Department of Chemistry "Ugo Schiff", via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy.
J Colloid Interface Sci. 2021 Jun 15;592:430-439. doi: 10.1016/j.jcis.2021.02.074. Epub 2021 Mar 2.
Pullulan, an exopolysaccharide consisting of maltotriose repeating units, has recently found many applications in different fields, such as food, packaging, cosmetics and pharmaceuticals. The introduction of photo-crosslinkable methacrylic units potentially allows to use pullulan derivative in inkjet 3D printing.
Pullulan was functionalized with methacrylic groups and the derivative was characterized by NMR, FT-IR and Raman spectroscopy. Water dispersions were thoroughly investigated by optical microscopy, SAXS and rheology to evaluate the self-assembly properties and they were used as photo-crosslinkable inks in a 3D printer, also in comparison with pristine pullulan. The structural and mechanical properties of the obtained films were studied by Atomic Force Microscopy and tensile strength tests.
The introduction of methacrylic groups moderately affects the self-assembly of the polymer in water, resulting in a slight increase of the gyration radius of the polymer coils and in a small decrease of the viscosity, retaining the typical shear-thinning behavior of concentrated polysaccharides in water. The structural and mechanical properties of the 3D printed films are much more affected, showing the presence of sub-micrometric phase segregated domains which are further separated by the cross-linking. As a result, the deformability of the materials is improved, with a lower tensile strength.
支链淀粉是一种由麦芽三糖重复单元组成的胞外多糖，最近在食品、包装、化妆品和制药等不同领域有许多应用。引入可光交联的甲基丙烯酸单元可能使支链淀粉衍生物可用于喷墨3D打印。
用甲基丙烯酸基团对支链淀粉进行功能化，并通过核磁共振、傅里叶变换红外光谱和拉曼光谱对衍生物进行表征。通过光学显微镜、小角X射线散射和流变学对水分散体进行了深入研究，以评估其自组装性能，并将其用作3D打印机中的可光交联墨水，同时与原始支链淀粉进行比较。通过原子力显微镜和拉伸强度测试研究了所得薄膜的结构和力学性能。
甲基丙烯酸基团的引入对聚合物在水中的自组装有适度影响，导致聚合物线圈的回转半径略有增加，粘度略有降低，同时保留了浓缩多糖在水中典型的剪切变稀行为。3D打印薄膜的结构和力学性能受到的影响更大，显示出存在亚微米级相分离域，这些域通过交联进一步分离。结果，材料的可变形性得到改善，拉伸强度降低。
