Curdlan acetate fibres with low degrees of substitution fabricated <i>via</i> a continuous process of chemical modification and wet spinning using an ionic liquid
Curdlan acetate fibres with low degrees of substitution fabricated <i>via</i> a continuous process of chemical modification and wet spinning using an ionic liquid
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<i></i>使用离子液体通过化学改性和湿纺连续工艺制造的低取代度凝胶多糖醋酸纤维
DOI：
10.1039/d1gc04336f
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发表时间：
2022
期刊：
影响因子：
9.8
通讯作者：
Iwata Tadahisa
中科院分区：
文献类型：
--
作者：
Suzuki Shiori;Togo Azusa;Kimura Satoshi;Iwata Tadahisa
具有低取代度（DS）的多糖酯有望成为生物质衍生的可生物降解塑料，具有可调节的性能，将取代传统的石油衍生塑料。然而，它们在模塑方面有困难，并且需要复杂的多步合成来控制它们的DS，从而限制了它们作为塑料的应用。在本研究中，我们展示了一个连续的过程中，均相乙酰化的凝胶多糖（β-1，3-葡聚糖）和反应物溶液的直接湿法纺丝，通过一致地使用离子液体，实现了既方便和绿色合成和制造凝胶多糖醋酸纤维的DS范围从0.1-1.0。可得然胶的部分乙酰化改善了热稳定性和纤维性质：热降解温度（Td-5%）从293 ° C至342 °C，杨氏模量（干）从2.9 GPa至4.0 GPa，湿强度从0.34 cN tex− 1至2.8 cN tex−1。最初，再生的可得然胶纤维是韧性的，具有85wt%的高吸水性，导致湿强度显著降低。相比之下，可得然胶醋酸酯纤维变硬，并且由于C4-OH基团的取代（其有助于水掺入可得然胶分子中），在DS = 0.8时吸水率被抑制至15重量%。因此，可得兰醋酸酯纤维的湿-干强度比从0.03显著提高到0.5。这种增强的性质归因于在DS超过0.4时通过乙酰化而改变晶体结构，从而防止经由C2-OH基团形成氢键（其稳定了原始三螺旋结构）。
Polysaccharide esters with a low degree of substitution (DS) are expected to be biomass-derived biodegradable plastics with tunable properties that will replace conventional petroleum-derived plastics. However, they have difficulties in moulding and complex multistep synthesis is required to control their DS, thereby limiting their application as plastics. In this study, we demonstrate a continuous process of homogeneous acetylation of curdlan (β-1,3-glucan) and direct wet spinning of the reactant solution by consistently using an ionic liquid, and achieve both facile and green synthesis and fabrication of curdlan acetate fibres with the DS ranging from 0.1–1.0. The partial acetylation of curdlan improved the thermal stability and fiber properties: thermal degradation temperature (Td-5%) from 293 to 342 °C, Young's modulus (dry) from 2.9 to 4.0 GPa, and wet tenacity from 0.34 to 2.8 cN tex−1. Originally, a regenerated curdlan fibre was ductile with a high water absorbency of 85 wt% causing a considerable decrease in wet tenacity. In contrast, curdlan acetate fibres stiffened and the water absorbency was suppressed to 15 wt% at DS = 0.8 owing to the substitution of the C4-OH group (which contributed to the incorporation of water into the curdlan molecules). Consequently, the wet-to-dry tenacity ratio of the curdlan acetate fibres significantly improved from 0.03 to 0.5. Such enhanced properties were attributed to the change in the crystalline structure by acetylation at the DS exceeding 0.4 with preventing the formation of hydrogen bonding via the C2-OH group (which stabilised the original triple helical structure).