Bone and teeth as fibrous biological composites: in situ nano-mechanical investigations

骨骼和牙齿作为纤维生物复合材料：原位纳米力学研究

基本信息

批准号：
EP/E039928/1
负责人：
Asa Barber
金额：
$ 30.05万
依托单位：
Queen Mary University of London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FE039928%2F1
关键词：
Bone teeth fibrous biological composites

项目摘要

Man-made composite materials are used extensively in a variety of structures where high strength and stiffness is required as well as low weight. These composites are almost exclusively constructed from a lightweight polymer reinforced with fibres. The fibres have advantages over other geometries as the mechanical properties are excellent in one particular direction, making the fibre anisotropic. The numerous structures existing in nature are optimized through evolutionary processes for a particular mechanical function. Common examples of biological materials with a mechanical role are bone, required for structural integrity in skeletal systems, and teeth, primarily used for chewing and tearing of food. These materials have striking resemblances to man-made composites as fibrous constituents are used as reinforcement in an organic matrix. However, two main differences are apparent in biological composites when compared to synthetic composites. The first is that the reinforcing fibres in biological composites are much smaller than typical fibres used in engineering composites. Decreasing fibre diameter is widely acknowledged to increase strength and utilization of scale effects in nature highlights the optimization processes used. Furthermore, many organizational levels exist in biological composites from the nano-scale level of the reinforcing fibre building blocks up to the large scale architectures. This structural hierarchy is currently far more complex than any synthetic composite.Understanding how the nano-scale fibre building blocks influence the overall mechanical properties of the biological composite is experimentally challenging due to the structural hierarchy and small size of the fibre reinforcements. Mechanical tests on large samples give results that are difficult to interpret because of the various different fibre organizations. Therefore, testing on the individual nano-scale fibre reinforcements in biological composites would give fundamental information and help to understand how materials like bone and teeth are optimized for their mechanical functions. In addition, the understanding of biological composites at the nano-scale could provide a pathway for developing new synthetic composites with nano-material reinforcements.The project will test samples of bovine bone femur and limpet teeth, which are representative of many different types of bone and teeth found in nature. The nano-scale fibres will be mechanical tested by pulling at the ends of these fibres. The pulling will be done by a scanning probe microscopy, which is ideal for measuring the very small forces needed to deform and break the nano-scale fibres. An electron microscope will also be used to visualize these tests and observe if the nano-scale fibres are fractured during the pulling process or slide out of the surrounding organic matrix. Mechanical models used in conventional composite theory will be applied to assess the mechanical properties of the reinforcing nano-fibres and the surrounding organic matrix. The results of this research will therefore provide unique insight into how natural materials have remarkable mechanical properties from using nano-scale building blocks.

人造复合材料广泛用于需要高强度和刚度以及低重量的各种结构。这些复合材料几乎完全由纤维增强的轻质聚合物制成。该纤维比其他几何形状具有优势，因为在一个特定方向上机械性能优异，使得纤维具有各向异性。自然界中存在的众多结构通过进化过程针对特定的机械功能进行了优化。具有机械作用的生物材料的常见例子是骨骼（骨骼系统中结构完整性所需的）和牙齿（主要用于咀嚼和撕裂食物）。这些材料与人造复合材料有着惊人的相似之处，因为纤维成分被用作有机基质中的增强材料。然而，与合成复合材料相比，生物复合材料有两个明显的差异。首先，生物复合材料中的增强纤维比工程复合材料中使用的典型纤维小得多。人们普遍认为，减小纤维直径可以提高强度，并且利用自然界中的尺度效应突出了所使用的优化过程。此外，生物复合材料中存在许多组织层次，从增强纤维构建块的纳米级到大规模结构。这种结构层次目前比任何合成复合材料都要复杂。由于结构层次和纤维增强材料的小尺寸，了解纳米级纤维构件如何影响生物复合材料的整体机械性能在实验上具有挑战性。由于纤维组织各异，对大样本进行的机械测试给出的结果难以解释。因此，对生物复合材料中的单个纳米级纤维增强材料进行测试将提供基本信息，并有助于了解如何优化骨骼和牙齿等材料的机械功能。此外，对纳米级生物复合材料的理解可以为开发具有纳米材料增强的新型合成复合材料提供途径。该项目将测试牛骨股骨和帽贝牙齿的样本，这些样本代表了许多不同类型的骨骼以及自然界中发现的牙齿。纳米级纤维将通过拉动这些纤维的末端进行机械测试。拉力将通过扫描探针显微镜完成，这非常适合测量使纳米级纤维变形和断裂所需的非常小的力。电子显微镜还将用于可视化这些测试，并观察纳米级纤维在拉伸过程中是否断裂或从周围的有机基质中滑出。传统复合材料理论中使用的力学模型将用于评估增强纳米纤维和周围有机基体的力学性能。因此，这项研究的结果将为了解天然材料如何通过使用纳米级构件而具有卓越的机械性能提供独特的见解。