Chitin nanofibers were prepared from commercially available chitin powder via esterification modification and subsequent ultrasound treatment. The obtained chitin nanofibers were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), ¹³C CP-MAS (cross-polarization under magic-angle spinning) solid state nuclear magnetic resonance (NMR), elemental analysis, and X-ray diffraction (XRD). Results showed that the esterification of chitin with maleic anhydride significantly improved the ultrasound disintegration of chitin fibrils into nanofibers. With increasing power and time, the ultrasound treatment yielded smaller chitin nanofibers with narrower size distribution, and the diameter of the chitin nanofibers could reach ∼15 nm. The effect of the ultrasound treatment on degree of acetylation and degree of substitution of the chitin nanofibers was negligible. However, crystallinity of the chitin nanofibers increased with increase in power and time of the ultrasound treatment.

中文翻译：

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通过酯化和超声处理制备和表征几丁质纳米纤维

甲壳质纳米纤维是通过酯化改性和随后的超声波处理，由可商购的甲壳质粉末制备的。使用动态光散射（DLS），扫描电子显微镜（SEM），傅立叶变换红外（FTIR）对获得的几丁质纳米纤维进行表征，¹³C CP-MAS（魔角旋转下的交叉极化）固态核磁共振（NMR），元素分析和X射线衍射（XRD）。结果表明，几丁质与马来酸酐的酯化作用显着改善了几丁质原纤维超声分解为纳米纤维的能力。随着功率和时间的增加，超声处理产生了较小的几丁质纳米纤维，具有较窄的尺寸分布，并且几丁质纳米纤维的直径可以达到约15nm。超声处理对甲壳质纳米纤维的乙酰化程度和取代度的影响可以忽略不计。然而，几丁质纳米纤维的结晶度随着超声处理的功率和时间的增加而增加。