Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia.
Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia.
Carbohydr Polym. 2019 Dec 15;226:115292. doi: 10.1016/j.carbpol.2019.115292. Epub 2019 Sep 4.
TEMPO/NaClO/NaBr and sodium periodate were combined in a one-shot reaction to oxidise cellulose from bleached pulp. Oxidation of cellulose forms two fractions: a highly-carboxylated water-insoluble (up to 1.9 mmol COO/g, DS = 0.39) and a water-soluble fraction (up to 4 mmol COO/g, DS = 1.1). Results show that these regioselective oxidants work in synergy to produce fully-oxidised 2,3,6-tricarboxycellulose. Increasing the periodate concentration results in fibrillation and extensive depolymerisation of the pulp cellulose as more residual aldehyde groups participate in the depolymerisation process. X-ray diffraction (XRD) reveals that the addition of periodate increases cellulose crystallinity, retains crystal size but slightly alters the XRD pattern. The degree of substitution (DS), which governs the solubility of carboxylated cellulose, can be controlled by varying the periodate concentration. Combining TEMPO/NaBr/NaClO with sodium periodate simultaneously in a one-shot reaction produces low-cost cellulose with controlled level of carboxylation and unique properties.
TEMPO/NaClO/NaBr 和高碘酸钠在一步反应中组合，将漂白浆中的纤维素氧化。纤维素的氧化形成两个部分：高度羧化的水不溶性部分（高达 1.9mmol COO/g，取代度为 0.39）和水溶性部分（高达 4mmol COO/g，取代度为 1.1）。结果表明，这些区域选择性氧化剂协同作用，生成完全氧化的 2,3,6-三羧基纤维素。增加高碘酸钠的浓度会导致纸浆纤维素的纤维化和广泛的解聚，因为更多的残留醛基参与解聚过程。X 射线衍射（XRD）表明，加入高碘酸钠会增加纤维素的结晶度，保持晶体尺寸，但略微改变 XRD 图谱。取代度（DS）控制着羧基化纤维素的溶解度，可以通过改变高碘酸钠的浓度来控制。TEMPO/NaBr/NaClO 与高碘酸钠在一步反应中同时使用，可产生具有可控羧化程度和独特性能的低成本纤维素。
