利用可生物降解性“壳聚糖/蒙脱土纳米复合材料”提高纸张阻隔性的研究

Biodegradable polymer/layers silicate nanocomposites have become a foucus of study in improving the barrier property of material recently. This item plans to make chitosan/montmorillonite nanocomposites with chitosan intercalating into the layers of montomorillonite via solution intercaltion method under untrosound. The research purpose is to improve the barrier of paper to oxygen and water vapour by the barrier coating on the surface of paper.The item will focus mainly on the following aspects:(1)Studying the effects of the different organic modification methods and synergies on the morphology structure of nanocomposites and exfoliation property of montomorillonite.(2)Analyzing influences of different molecular weight and degree of deacetylation of chitosan on critical aggregation concentration,surface properties and absorption of montomorillonite.(3)Discussing the effects of rheological behavior and migration of nanocomposites system on the film properties，barrier ability and thermodynamics and kinetics for gas.Theoretical basis of controlling the lay spacing of montmorillonite and dispersion stability will be obtained.It will grasp the regularities that chitosan with different deacetlation affects the absorbtion ability to monorillonite and its intercaltion driving force.The effictive means that evaluates the dispersion state of montmorillonite in the chitosan substrate will be founded.The penetration model of gas through the barrier film will be established also.It will found the relation among microstructure，reheological behavior and barrier.The research will found reliable theories and techniques for improving the barrier of paper to oxygen and water vapour and broadening the application scope of paper.

可生物降解性聚合物/层状硅酸盐纳米复合材料性能优异，目前已成为提高材料阻隔性的研究热点。本项目拟采用超声波-溶液插层法，制备壳聚糖/蒙脱土纳米复合材料，采用阻隔涂布的方式，提高纸张阻隔性能。拟研究不同有机改性方法及其协同作用对壳聚糖/蒙脱土纳米结构形态和蒙脱土剥离特性的影响；壳聚糖脱乙酰度、分子量对蒙脱土临界聚集浓度、表面性能和吸附性能的影响；壳聚糖/蒙脱土纳米复合材料"流变行为"和"迁移"对成膜性、阻氧阻湿性和对气体传输热力学和动力学的影响。研究将获得控制有机蒙脱土层间距、分散稳定性的理论依据，掌握不同脱乙酰度壳聚糖对蒙脱土吸附性能和对壳聚糖插层驱动力的影响规律；建立通过"流变行为"评价纳米粒子在聚合物基体中分散状态的有效手段，建立预测气体通过阻隔性纳米薄膜的渗透数学模型,揭示微观结构、阻隔性与流变行为之间的关系。为提高纸张阻隔性能，拓宽纸质包装材料的应用范围奠定可靠的理论和技术基础

可生物降解性聚合物/层状硅酸盐纳米复合材料性能优异，将其通过表面涂布的方式涂覆在纸张表面，能提高传统纸张的阻隔性能。本项目采用了超声波-溶液插层法，制备了壳聚糖/蒙脱土纳米复合材料，采用阻隔涂布的方式，提高纸张对氧气和水蒸气的阻隔性能，以达到拓宽包装纸的应用范围之目的。研究的主要内容包括：不同有机改性方法及其协同作用对壳聚糖/蒙脱土纳米结构形态和蒙脱土剥离特性的影响；壳聚糖脱乙酰度、分子量对蒙脱土临界聚集浓度、表面性能和吸附性能的影响；壳聚糖/蒙脱土纳米复合材料“流变行为”和“迁移”对成膜性、渗透性、阻氧阻湿性和对气体传输热力学和动力学的影响。研究发现：偶联剂不仅对蒙脱土有表面修饰作用，而且能够进入蒙脱土层间。双重改性能提高蒙脱土与有机溶剂的相容性。超声波振荡能明显提高蒙脱土在壳聚糖中的分散性能，减少蒙脱土的絮聚现象。甘油增塑剂能够提高涂布纸的柔韧性，但降低了涂布纸的抗水性和阻湿性。随着壳聚糖脱乙酰度的增大，壳聚糖/蒙脱土纳米复合涂布纸的氧气透过率增加，水蒸气透过率下降。壳聚糖进行羧甲基化改性和季铵基团改性能有效增加壳聚糖的水溶性；羧甲基壳聚糖的季铵化，季铵盐壳聚糖羧甲基化，能使壳聚糖衍生物表现出两性特征。壳聚糖/蒙脱土纳米复合涂料表现出剪切变稀的假塑性流体特性。原纸施胶度是影响壳聚糖/纳米复合材料以及单一壳聚糖成膜性的主要影响因素。研究获得了控制有机蒙脱土层间距、分散稳定性的理论依据和控制方法，掌握了不同脱乙酰度壳聚糖对蒙脱土吸附性能和对壳聚糖插层驱动力的影响规律；建立通过“流变行为”评价纳米粒子在聚合物基体中分散状态的有效手段，建立预测气体通过阻隔性纳米薄膜的渗透数学模型,揭示微观结构、阻隔性与流变行为之间的关系。为提高纸张阻隔性能，拓宽纸质包装材料的应用范围奠定可靠的理论和技术基础。