The Science Underpinning Anomalous Scaling Laws of Strength and Toughness in Nanocellulose Materials

支持纳米纤维素材料强度和韧性异常缩放定律的科学

• 批准号: 1362256
• 负责人: Teng Li
• 金额: $ 40万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1362256&HistoricalAwards=false
• 关键词: Science; Underpinning; Anomalous; Scaling; Laws

The quest of materials possessing both high strength and high toughness is perpetual in advanced material design. Unfortunately, these two mechanical properties are generally mutually exclusive. For example, for metals and alloys, their toughness is usually inversely proportional to their strength. As a result, in practice, the design of strong and tough materials is inevitably a compromise. So far, a general and feasible mechanism to address the conflict of strength vs. toughness still remains elusive. This project plans to shed insight on a possible strategy resolving the conflict of strength vs. toughness by investigating the fundamental science of the anomalous but desirable scaling law of mechanical properties of cellulose nanopaper: both its strength and toughness increase as the cellulose fiber size decreases. These unique features combined with the intrinsic biodegradability, low-cost and scalable manufacturing of cellulose paper can have significant impact on bottom-up design of high performance materials with desirable mechanical properties. The research plan will be carried out in a systematic framework integrating multi-scale mechanics modeling and complementary experiments and consists of two thrusts. The overarching goal of Thrust 1 is to establish a quantitative understanding of the underpinning mechanism of both strong and tough cellulose nanopaper, by investigating the mechanics of cellulose molecular chains, nanofibrillated cellulose fibers and cellulose fiber network via multi-scale mechanics modeling and complementary experiments. The fundamental understanding from Thrust 1 will lay out a solid foundation that motivates and enables the research efforts in Thrust 2, which focuses on generalizing the underpinning mechanism of attaining both strength and toughness to guide the exploration of a class of strong and tough materials with other highly desirable multi-functionalities. Interdisciplinary graduate student training will enable to access world-class imaging and metrology facilities at NIST, and to learn from the vast expertise and state-of the-art technology from a world leading paper company. Outreach activities will be conducted via iMechanica.org, the largest international online community of mechanics with 50,000+ registered users.

在高级材料设计中，对拥有高强度和高韧性的材料的追求永远是永久的。不幸的是，这两种机械性能通常是相互排斥的。例如，对于金属和合金，它们的韧性通常与它们的力量成反比。结果，在实践中，强大而坚固的材料的设计不可避免地是妥协。到目前为止，解决力量冲突与韧性的一般且可行的机制仍然难以捉摸。该项目计划通过调查纤维素纳米蛋白的机械性能的异常但理想的扩展定律的基本科学来了解解决力量与韧性的可能策略：其强度和韧性随着纤维素纤维尺寸的减小而增加。这些独特的特征结合了纤维素纸的内在生物降解性，低成本和可扩展性的制造可能会对具有理想的机械性能的高性能材料的自下而上设计产生重大影响。该研究计划将在整合多尺度力学建模和互补实验的系统框架中执行，并由两个推力组成。推力1的总体目标是通过研究纤维素分子链，纳米纤维纤维纤维纤维和纤维素纤维网络通过多尺度机械模型和互补实验的实验来建立对强纤维素纳米蛋白的基础机制的定量理解。推力1的基本理解将奠定一个坚实的基础，激励和促进推力2的研究工作，该研究的重点是推广具有实力和韧性的基础机制，以指导与其他与其他材料一起探索一类强壮的材料高度理想的多功能性。跨学科的研究生培训将使NIST访问世界一流的成像和计量设施，并从一家世界领先的造纸公司那里学习庞大的专业知识和最先进的技术。外展活动将通过Imechanica.org进行，这是最大的国际在线机械社区，拥有50,​​000多名注册用户。