Material Processing and Mechanical Behavior of High-Performance Cellulose Nanopaper Made From Cellulose Nanofibrils

这项拨款将使研究能够开发纤维素纳米纤维自组装制成的纤维素“纳米纸”，用于结构应用。具有轻质特性的坚固、坚硬和坚韧的材料对于从汽车到航空工业的许多工程应用至关重要，以减少能源消耗并提高结构灵活性等。本研究的目的是创造绿色替代传统的化石燃料衍生的聚合物和聚合物复合材料，采用纤维素纳米纤维衍生的木质纤维素生物质作为替代石油为基础的资源。教育和培训学生从不同的和代表性不足的群体在加工领域的绿色材料和机械表征和建模的新型纳米结构材料通过非接触，基于视觉的方法是整体研究目标的一部分。 将研究成果纳入研究生课程，通过演示，演讲，出版物和其他外联活动向同行和整个社区传播研究结果也是研究项目的组成部分。纤维素纳米原纤维所具有的高纵横比和半结晶纳米结构使其成为形成三维缠结微观网络的理想选择，该三维缠结微观网络适用于通过自组装加工高性能结构材料。所得到的材料通常被称为纤维素纳米纸，并具有有前途的机械特性。这项基础研究，在“原样”和功能化状态下纤维素纳米纸的材料加工和机械行为的界面上，是为了破译这种非传统和潜在的变革性材料的高性能机械应用的过程-微观结构-性能关系。在材料加工方面，重点将放在（a）研究与环境友好的甲酸水解和机械原纤化参数相关的反应条件对纤维素纳米原纤特性的影响，（B）研究不同的加工方法以控制所得纳米纸的质量、微观结构和功能。在机械表征方面，重点将是（a）发展对不同长度尺度和加载速率下不同微观结构和功能的纤维状纤维素纳米纸的拉伸和断裂响应的基于力学的理解，（B）开发和演示单片和层压高-该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的知识产权评估的支持。优点和更广泛的影响审查标准。

This grant will enable research on developing cellulose ‘nanopaper’ made by self-assembly of cellulose nanofibrils for structural applications. Strong, stiff and tough materials with lightweight characteristics are critical for many engineering applications ranging from automotive to aviation industries to reduce energy consumption and increase structural agility, among others. This research aims to create green alternatives to traditional fossil fuel derived polymers and polymer composites by employing cellulose nanofibrils derived from lignocellulosic biomass as an alternative to petroleum-based resources. Educating and training students from diverse and underrepresented groups in areas of processing of green materials and mechanical characterization and modeling of novel nanostructured materials via non-contact, vision-based approaches is part of the overall research goal. Incorporating the research outcomes into the graduate curriculum, disseminating the findings to peers and the community at-large through demonstrations, presentations, publications and other outreach activities is integral to the research project as well. The high aspect ratio and semi-crystalline nanostructure that cellulose nanofibrils possess make them ideal to form three-dimensionally entangled microscopic networks suitable for processing high-performance structural materials via self-assembly. The resulting material is often referred to as cellulose nanopaper and has promising mechanical characteristics. This basic research, at the interface of material processing and mechanical behavior of cellulose nanopaper in ‘as-is’ and functionalized states, is to decipher process-microstructure-property relations for this non-traditional and potentially transformative material for high performance mechanical applications. On the material processing front, the focus will be on (a) studying the reaction conditions associated with the environmentally-friendly formic acid hydrolysis and mechanical fibrillation parameters on the cellulose nanofibril characteristics, (b) investigating different processing approaches to control the resulting nanopaper quality, microstructure and functionality. On the mechanical characterization front, the focus will be on (a) developing mechanics-based understanding of the tensile and fracture responses of fibrous cellulose nanopaper of different microstructures and functionalities at different length scales and loading rates, (b) developing and demonstrating monolithic and laminated high-performance cellulose nanopaper structures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.