蒙脱土增强的复合塑化体系中高直链玉米淀粉结构演变规律与分子模拟

Environmental pollution caused by nonbiodegradable food packaging films is more and more serious with the rapid development of national convenient food and fast food industries. Starch nannocomposite films have been regarded as the most promising fully biodegradable food packaging films by domestic and foreign scientists. On the whole, there hasn't been much production and application of biodegradable starch-based food packaging films. The absence of related basic theory is the main reason for the problem, added to the lack of continuous and highly efficient production process. Based on our previous studies, the starch nanocomposite films are prepared with stabilized and cross-linked high amylose maize starches,enhanced by modified montmorillonites with different interfacial characteristics and plasticized by combination of various plasticizers. The granular and molecular structure evolutions of the starches will be investigated during melt intercalation, film blowing and storage of the films. The effects of the starch structure evolutions on formation of starch nanocomposites and their properties are also studied. The molecular mechanism of film forming of starch nanocomposites will be illustrated. Moreover, the molecular interactions between starch-plasticizer-montmorillonite and compatibilities of various components will be discovered by molecular dynamics simulation. The forming mechanism of starch nanocomposite will be discovered at molecular level. A new theory will be provided for the development and application of starch-based food packaging films with high performance.

随着我国方便食品和快餐食品业的高速发展，非降解食品包装膜造成的环境污染日益严重。淀粉纳米复合材料膜已被国内外学者公认为最有发展前景的全降解食品包装膜。但总体而言，淀粉基食品包装膜的生产和应用还十分有限。除了缺乏高效连续的制膜工艺之外，相关基础理论的匮乏是造成这一问题的关键所在。本项目在前期研究的基础上，采用稳定化交联复合变性的高直链玉米淀粉为成膜基材，以具有不同界面特性的改性蒙脱土为增强剂，采用复合塑化体系，研究在熔融插层、挤出吹膜及产品放置过程中，淀粉颗粒结构与分子结构的演变规律及其对淀粉纳米复合材料形成和性能的影响，从而阐明淀粉纳米复合材料成膜的分子机制。同时，通过分子动力学模拟，研究淀粉-增塑剂-蒙脱土体系中分子间相互作用和组分相容性，从分子水平上揭示淀粉纳米复合材料成膜机理。本项目的预期成果将为高性能淀粉基全降解食品包装膜的开发和应用提供新的理论依据。

传统石油基食品包装材料造成的环境污染日益严重。淀粉纳米复合材料被国内外学者认为是最有发展前景的生物降解材料。为了克服现有淀粉基材料的缺陷，本项目从复合增塑剂的选择，淀粉的改性方式与改性程度，蒙脱土的改性方式和改性程度，淀粉膜吹塑工艺和贮藏条件等方面，研究了淀粉纳米复合材料形成的机理及其与性能的关系。结果表明：疏水性增塑剂与甘油相复配，可以有效增塑淀粉/有机改性蒙脱土，淀粉膜的表面更加平整、光滑，淀粉膜的机械性能和阻隔性能得到显著提高。项目揭示了增塑剂对淀粉蒙脱土纳米复合材料的形成及其性能的影响规律，阐明了淀粉轻度改性、蒙脱土表面疏水改性与淀粉结构演变、淀粉纳米复合材料性能的关系，制备了具有良好机械性能、阻隔性能的淀粉蒙脱土纳米复合材料。项目的研究成果为我国淀粉基全降解材料的开发与应用提供理论基础。项目共发表SCI论文9篇，授权发明专利1项。以本项目的理论为指导，开发的高性能淀粉纳米复合材料的制备技术获2017年度山东省技术发明二等奖1项。