层层自组装增强及超疏水改性纸质包装材料及机理研究

With the growing importance of environmental protection and the implementation of the “plastic limit” policy in China, renewable cellulosic fiber-based packaging materials with high strength and superhydrophobic properties have attracted considerable attention. These fiber-based packaging materials have potential application in partial or whole replacement of plastic packaging materials. In this proposal, some attempts will be made to prepare high strength and superhydrophobic packaging paper through building up nanostructured multilayers composed of natural polysaccharides and their derivatives or inorganic nanoparticles on the cellulosic fiber surface by layer-by-layer (LBL) self-assembly technique. The incompatibilities between strengthening modification and superhydrophobic modification will be coordinated, and the LBL system having strengthening and superhydrophobic modification functions will be constructed. The study content as follows: (i) The LBL multilayers will be constructed on cellulosic fiber surface using different LBL strategies respectively. Surface characters, growth manner and formation mechanisms of multilayers will be studied. (ii) The effect of LBL multilayers built from different LBL system on paper strength and wetting properties will be investigated. (iii) Coordinate the incompatibilities between strengthening modification and superhydrophobic modification. (iv) The strengthening and superhydrophobic modification mechanisms of LBL multilayers will be explored. The study results of this proposal will provide theoretical basis for strengthening and superhydrophobic modification of cellulosic fibers, as well as basis support for cellulosic fibers application in green packaging industry.

随着全球对环境保护的日益重视及我国限塑令的推出和实施，利用可再生植物纤维原料制备高强度超疏水纸或纸板，部分或逐步取代塑料作为包装材料具有重要现实意义。本项目基于层层自组装技术，选用可再生、无毒、来源丰富的天然多糖及其衍生物、无机纳米粒子作为自组装材料，在植物纤维表面构筑纳米级的多层膜对其进行改性，制备具有较好强度性能的超疏水包装用纸。协调增强改性和超疏水改性的不兼容性，构建兼具增强和超疏水改性的层层自组装体系。具体内容包括：采用不同的自组装方案分别在植物纤维表面制备多层膜，首先研究多层膜的表面特性、成膜方式及成膜机制；考察不同的多层膜对成纸强度和表面润湿性能的影响；协调成纸增强改性和超疏水改性不兼容的问题；最后进一步探讨多层膜对成纸的增强和超疏水改性机理。预期研究成果可为层层自组装技术用于植物纤维基包装用纸增强及超疏水改性提供理论依据，为植物纤维原料在绿色包装行业的广泛应用提供基础支撑。

作为地球上储量最为丰富的可再生资源的植物纤维，具有价格低廉、无毒、生物可降解性等优点，以其为基体制备的纸质包装材料被认为是一种具有前途的绿色包装材料。然而天然植物纤维具有强亲水性，限制了纸质包装材料的实际应用范围，故需要对其进行修饰改性，以制备具有较好强度性能的超疏水纸质包装材料。然而，纸张增强改性和超疏水改性二者具有不可兼容性，本项目通过构建几个合理的层层自组装改性体系有效地解决了这个矛盾体。以天然多糖及其衍生物、无机纳米粒子作为组装材料，研究了不同层层自组装体系多层膜的表面特性、成膜方式及成膜机制，探讨不同多层膜对纸张强度和表面润湿性的影响，阐明了多层膜对成纸强度和超疏水改性的主要机制。本项目研究成果可为层层自组装技术用于纸张增强及超疏水改性提供技术参考，为植物纤维作为绿色包装材料的广泛应用提供基础支撑。