水力缠结木桨基纤维集合体微观结构特征与分散机理研究

Disposable sanitary wipes are discarded into sewer after use, resulting in the serious problem of urban pipe blockage. Dispersible hydroentanglement wood pulp-based fiber aggregation used as wipe is an effecitive way to solve the problem. In this project, micro-CT technology was used to reconstruct the long and short fiber aggregation, and the tomography(CT) images were processed by median filter, grayscale and binarization. The fault plane fractal dimension of each material was calculated by the counting box dismension method and the least square method. The digital image analysis method was used and the material dispersion device was designed in the material dispersion process. The process images were processed by Photoshop and the pixel transformation was used to investigate the function between the material residual rate and dispersion time. The theoretical model between the fractal dimension of microstructure characterization and dispersion process was established. Meanwhile, the relationship between fault plane fractal dimension and processing parameters was discussed. These can optimize the preparation of dispersible wood pulp-based fiber aggregation. Finally, the dispersion mechanism of hydroentanglement fiber aggregation was revealed by processing parameters, 3d microstructure characteristics, crowding factors of fiber-water system and dispersion process. Overall, it can provide a theoretical basis for use of the long and short fiber aggregation in dispersible health care products, and can also optimize the production process and reduce the expensive experiment and development cost of new products.

用即弃卫生护理纸巾用后弃入下水道引起城市管道堵塞问题日趋严重，可分散水力缠结木桨基纤维集合体基材是解决该问题的有效途径。本项目利用Micro-CT技术三维重构水力缠结木桨基长短纤维集合体，中值滤波灰度化二值化处理断层彩图，根据计盒维数法与最小二乘法计算各材料断层面分形维数。采用数字图像分析方法，设计搭建材料分散装置，利用Photoshop软件处理过程图并像素转化研究材料分散剩余率随时间的变化函数。建立材料微观结构特征层面分形维数与分散过程的理论模型，同时讨论材料层面分形维数与加工参数间关系，优化可分散木桨基纤维集合体的制备。最终综合加工参数、三维微观结构特征、纤维-水分散体系拥挤因子和分散过程等，揭示水力缠结纤维集合体的分散机理。可为高速水针射流加固长短纤维集合体用于可分散卫生护理用品提供理论依据，也可优化生产工艺且减少昂贵的新产品试验开发成本。

用即弃卫生护理纸巾用后丢入抽水马桶易引起城市管道堵塞，水力缠结可分散木浆基纤维集合体作为基材可有效解决该问题，但对材料分散过程与机理尚未有定论。项目从众多加工参数（木浆纤维含量、水针射流压力和、克重、短切纤维种类、线密度、长度等）出发制备木浆基纤维集合体材料，利用Micro-CT技术提取材料内部三维结构和断层彩图，根据计盒维数法和最小二乘法计算各材料层面分形维数，利用数字图像分析研究材料分散过程函数，构建材料整体层面分形维数与材料分散过程理论模型。同时，讨论材料层面分形维数与加工参数间关系，优化可分散木桨基纤维集合体的制备。得出木浆基纤维集合体中木浆纤维为主体，短切纤维作为增强，集合体两侧向内层面孔隙率逐渐减少，到中心的层面孔隙率在67%左右，层面分形维数介于1-2之间且呈规律性变化。木浆基纤维集合体的分散是先由主体木浆纤维瓦解，后短切纤维解体分散，分散过程可分为四阶段（分散速率低、分散速率快速上升、分散速率快速下降、分散与絮聚共存），木浆基纤维集合体分散随时间的变化曲线可用玻尔兹曼模型进行拟合，达到分散平衡时拥挤因子在14-60之间，拥挤因子的增加扩大所需分散过程时间，Lyocell/木浆纤维集合体在较低水针压力和（190 bars）达到良好的湿强与分散平衡。项目研究促进可分散木浆基水力缠结纤维集合体可控制备，同时可逐步应用于熔喷、纺粘、针刺等材料结构与性能的研究中。

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