Abstract Contributions of ultrasonic wave, metal ions and oxidation on the degree of polymerization (DP) of microcrystalline cellulose (MCC) were evaluated. Five transition metal ions, namely, Ni2+, Cu2+, Co2+, Mn2+, and Fe2+, were selected. H2O2, as an oxidizing agent, was also investigated. Changes in the structure of MCC induced by the ions were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, and field-emission scanning electron microscopy. Results indicated that DP decreased by 16.6%, 32.8%, 47.9% using U-MCC, Ni2+/U-MCC, and O Ni2+/U-MCC, respectively. DP of MCC was reduced from 195 to 101.5 under O Ni2+/U-MCC due to the destruction of interchain-hydrogen bond. Kinetic of depolymerization process for MCC obeyed the equation: DP = 102.2 + 93.8e−0.000798t, with activation energy of 17.33 kJ/mol. The result suggests that depolymerization of MCC was mainly a physical process at these conditions, and the interchain-hydrogen bond were disrupted. This study is beneficial for the deep hydrolysis and its utilization of MCC.

中文翻译：

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超声波、金属离子和氧化作用对纤维素解聚及其动力学的贡献

摘要 评价了超声波、金属离子和氧化作用对微晶纤维素 (MCC) 聚合度 (DP) 的影响。选择了五种过渡金属离子，即 Ni2+、Cu2+、Co2+、Mn2+ 和 Fe2+。还研究了 H2O2 作为氧化剂。由离子引起的 MCC 结构的变化通过傅里叶变换红外光谱、X 射线衍射和场发射扫描电子显微镜进行了表征。结果表明，使用 U-MCC、Ni2+/U-MCC 和 O Ni2+/U-MCC，DP 分别降低了 16.6%、32.8%、47.9%。由于链间氢键的破坏，MCC 的 DP 在 O Ni2+/U-MCC 下从 195 降低到 101.5。MCC的解聚过程动力学遵循方程：DP = 102.2 + 93.8e-0.000798t，活化能为17.33 kJ/mol。结果表明，在这些条件下，MCC 的解聚主要是一个物理过程，链间氢键被破坏。该研究有利于MCC的深度水解及其利用。