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首页> 外文期刊>Journal of Applied Polymer Science >Effect of carboxyl content on the physicochemical properties and intramolecular water distribution of 6-carboxyl chitooligomer prepared by laccase-TEMPO
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Effect of carboxyl content on the physicochemical properties and intramolecular water distribution of 6-carboxyl chitooligomer prepared by laccase-TEMPO

机译：羧基含量对Laccase-Tempo制备的6-羧基氯离苯脲的物理化学性质和分子内水分布的影响

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摘要

6-carboxyl chitooligomer was prepared by degradation of chitosan with H2O2 followed by catalytic oxidation in the laccase-2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) system. The TEMPO was used as a single variable to alter the content of introduced carboxyl groups. The resulting oxidation products were analyzed by ion chromatography, scanning electron microscopy, and H-1 low-field NMR. Moisture absorption-retention ability, antioxidation, and thermal stability also were characterized. The results showed that the carboxyl content in the molecules increased with increasing TEMPO. With the addition of 8% TEMPO (mass fraction relative to chitooligomers), the carboxyl content and the oxidation degree of the product reached 4.90 mmol/g and 96.53%, respectively. Under these conditions, it also had the highest ABTS radical cation scavenging ability of 85.47% and improved thermal stability. When the amount of TEMPO was reduced to 2%, the oxidation product had a degree of oxidation of similar to 50% and showed a unique molecular structure and supreme moisture absorption-retention ability. A higher associated water content was observed inside the molecules where more bound water was locked in the process of moisture absorption. Furthermore, the physicochemical properties of 6-carboxyl chitooligomer were much higher than chitooligomer and oligomeric sodium hyaluronate (HA-Oligo). (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47509.
机译：通过用H 2 O 2降解壳聚糖，然后在胰凝聚酶-2,2,6,6-四甲基哌啶-1-氧基（Tempo）体系中催化氧化来制备6-羧基氯离脱球剂。速度用作单个变量以改变引入的羧基的含量。通过离子色谱，扫描电子显微镜和H-1低场NMR分析所得氧化产物。还表征了吸湿保留能力，抗氧化和热稳定性。结果表明，分子中的羧基含量随着速度的增加而增加。加入8％的速度（相对于氯离子剂的质量分数），羧基含量和产物的氧化程度分别达到4.90mmol / g和96.53％。在这些条件下，它还具有85.47％的最高机密阳离子清除能力和改善的热稳定性。当节奏量减少到2％时，氧化产物具有与50％相似的氧化程度，并且显示出独特的分子结构和最高的吸湿保留能力。在分子内观察到更高的相关水含量，其中更多结合的水被锁定在吸湿过程中。此外，6-羧基氯离脱球剂的物理化学性质远高于氯离苯寡球和低聚透明质酸钠（Ha-Oligo）。 （c）2019 Wiley期刊，Inc.J.Phill。聚合物。 SCI。 2019,136,47509。

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