冷冻干燥法制备纤维素基多孔材料的研究

发布时间：2018-04-06 00:38

本文选题：植物纤维　切入点：冷冻干燥　出处：《中国造纸》2017年11期

【摘要】：以植物纤维为原料,研究了利用冷冻干燥法制备纤维素基多孔材料过程中纤维悬浮液浓度和冷冻温度对多孔材料微观结构和性能的影响,并探讨了冷冻过程中冰晶对纤维的作用方式和多孔材料微观结构的形成机制。结果表明,随着纤维悬浮液浓度的升高,冰晶的结构从平面状演变为层状,导致多孔材料的Z向微观形貌从各向同性转变为各向异性层状孔隙结构,有助于提高其抗欧拉失稳能力,使应力-应变曲线平压区缩短,密实化区向低应变点偏移。随着冷冻温度降低,冰晶凝固前沿处纤维受到的黏滞阻力增大,从而使其被冰晶吞没而均匀分散,材料两面差减少;另外,降低冷冻温度可降低层状冰晶的厚度,使多孔材料Z向孔隙尺寸减小,有助于提高其抵抗应力变形的能力,使应力-应变曲线中的密实化区向低应变点偏移。
[Abstract]:The effects of the concentration of fiber suspensions and freezing temperature on the microstructure and properties of cellulosic porous materials prepared by freeze-drying method were studied using plant fibers as raw materials.The effect of ice crystal on fiber and the formation mechanism of porous material microstructure were also discussed.The results show that with the increase of the concentration of fiber suspensions, the structure of ice crystals changes from plane to layered, which leads to the transformation from isotropy to anisotropic pore structure of Z micromorphology of porous materials.It is helpful to improve the ability of resisting Euler instability, shorten the stress-strain curve and shorten the pressure area of stress-strain curve, and shift the compaction zone to the low strain point.With the decrease of freezing temperature, the viscosity resistance of the fibers at the solidification front of ice crystals increases, so that the fibers are swallowed and dispersed uniformly by ice crystals, and the difference between the two sides of the materials is reduced, in addition, the thickness of layered ice crystals can be reduced by lowering the freezing temperature.The Z direction pore size of porous material is reduced, which is helpful to improve its ability to resist stress and deformation, and the compaction zone in stress-strain curve is shifted to low strain point.
【作者单位】：陕西科技大学轻工科学与工程学院中国轻工业纸基功能材料重点实验室;轻化工程国家级实验教学示范中心(陕西科技大学);
【基金】：国家重点研发计划(2017YFB0308300) 东华大学国家重点实验室开放基金(LK1601) 国家自然科学基金(31670593) 陕西省重点研发计划项目(2017GY-140)
【分类号】：TB383.4

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