Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
Carbohydr Polym. 2023 Apr 15;306:120618. doi: 10.1016/j.carbpol.2023.120618. Epub 2023 Jan 26.
Thermoplastic starch was prepared from tapioca starch (TS) and thermo-mechanical modified TS (ModifiedTS) using glycerol as a plasticizer and cellulose nanofiber (CNF) as a reinforcement. The ModifiedTS was produced using shear-and-heat milling machining (SHMM), which effectively reduced starch crystallinity and transformed the granule shape without a chemical reaction. The modified starch with low crystallinity and numerous active hydrogen bonds clearly showed Vh crystal structure after blending with glycerol. The mechanical properties changed significantly upon addition of 10 wt% CNF into plasticized ModifiedTS, which enhanced the yield strength and decreased the elongation at break. A dynamic mechanical analysis revealed a higher glass transition temperature (Tg) of the ModifiedTS films. Tg for the starch film increased from 9.3 °C of the TS film to 29.8 °C of the ModifiedTS film. These results suggest that SHMM provides the ability to widely adjust the mechanical properties of glycerol plasticized starch materials by enhancing interfacial interactions with CNF.
采用甘油作为增塑剂，纤维素纳米纤维（CNF）作为增强剂，从木薯淀粉（TS）和热机械改性 TS（改性 TS）制备热塑性淀粉。改性 TS 采用剪切和热磨加工（SHMM）生产，该加工方法在不发生化学反应的情况下，有效地降低了淀粉结晶度并改变了颗粒形状。经过与甘油混合后，具有低结晶度和大量氢键的改性淀粉明显显示出 Vh 晶体结构。在增塑改性 TS 中添加 10wt% CNF 可显著改变力学性能，提高屈服强度，降低断裂伸长率。动态力学分析显示改性 TS 薄膜具有更高的玻璃化转变温度（Tg）。淀粉薄膜的 Tg 从 TS 薄膜的 9.3°C 增加到改性 TS 薄膜的 29.8°C。这些结果表明，SHMM 通过增强与 CNF 的界面相互作用，为广泛调整甘油增塑淀粉材料的力学性能提供了可能性。
