微晶纤维素机械力化学处理结构变化研究

Structural Changes of Microcrystalline Cellulose During Mechanochemical Treatment

使用行星球磨机处理微晶纤维素,研究了研磨时间对纤维素结构变化的影响。用多晶X射线衍射(XRD)、红外吸收光谱(FTIR)、激光粒度(LPSA)和偏光显微镜,对机械力处理后纤维素样品的结晶度、晶粒度、粒度分布和形貌进行了表征。研究表明,在180min的研磨过程中,随研磨时间的延长,样品的结晶度持续降低,颗粒团聚程度增加,而晶粒度在120min后即达到极小值((002)方向7.8nm)。研磨产物的粒度分布均呈二峰特征,且粒度分布范围随处理时间延长而减小。机械力处理破坏了微晶纤维素结构中的氢键网络,增加了结构的松弛性。

Microcrystalline cellulose （MCC） was subjected to mechanical treatment to evaluate the structural changes upon planetary ball milling. Samples were characterized by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR）, laser particle size analyzer （LPSA） and polarized optical microscopy. During a 180 min grinding, a continuous reduction of crystallinity together with aggregation of the particles was observed. The crystallite size of the 120 min treated sample approached a saturation value （ca. 7. 8 nm in the （002） direction）. It was found that the treated samples showed a bimodal and a narrower particle size distribution with increasing of milling time. Mechanical treatment produced a gradual destruction of the hydrogen-bonding networks in the MCC samples, which resulted in its structural relaxing.