蜘蛛丝优异力学性能的结构机理及其模化

【作者】 潘志娟；

【导师】 李栋高；

【作者基本信息】 苏州大学 ， 纺织工程， 2002， 博士

【摘要】 生体高分子纤维因其固有的生体功能而被广泛应用于纺织、医学、生物等领域，自20世纪90年代以来又出现了许多仿生和超生高分子纤维材料，并将开发的热点转向高强轻质的新型纤维。蜘蛛因具有许多天然纤维甚至高性能合成纤维无法比拟的优异力学性能，而成了国内外许多研究机构和学者关注的焦点，近年来，国外的学者在研究蜘蛛丝结构和性能的同时，借助于日益发展的生物技术，采用基因移植的方法研制了人工合成蜘蛛丝蛋白，并采用化学纤维纺丝的方法将其制成类蜘蛛丝，但由于性能上的缺陷、加工过程复杂、成本高等因素，仿蜘蛛丝尚未实现工业化生产。从材料科学的角度来看，纤维的性能取决于其大分子链结构和聚集态结构，探明纤维性能形成机理的根本在于：掌握其结构和性能间的本构关系。因此，要使蜘蛛丝的力学性能在人造生体高分子纤维上得到表达，研究其性能的结构机理和形成这种结构的方法原理是至关要的。本文以广泛分布于我国各地的大腹圆蛛为研究对象，在研究分析其三种主要的丝纤维——牵引丝、蛛网框丝、包卵丝的力学性能、色泽、密度与吸湿性以及热学性能的基础上，从以下几方面探索了蜘蛛丝优异力学性能的形成机理。研究了蜘蛛丝力学性能的分子基础 分析大腹圆蛛丝纤维的氨基酸组成特征，并通过与其他种类蜘蛛丝及蚕丝丝素纤维的比较，研究蜘蛛丝的氨基酸组成对其分子结构和分子排列的影响。采用激光拉曼光谱和红外光谱技术，分析了不同功能蜘蛛丝的分子构象，探索了蜘蛛丝的氨基酸组成及分子结构和其力学性能间的关系。蜘蛛丝优异力学性能的结构机理及其模化摘要研究了蜘蛛丝力学性能与微观结构的关系采用x射线衍射技研究和分析了蜘蛛丝的结晶结构及其取向。通过对蜘蛛丝的物理、化学处利用扫描电镜观察和分析了蜘蛛丝的微观结构特征，发现了蜘蛛丝具有皮术理芯层结构和原纤化构造。分析了结晶度不足10%的蜘蛛丝具有高强度和高伸长的原因，研究了皮芯层结构对蜘蛛丝力学性能的影响以及不同功能蜘蛛丝应力一应变行为差异的形成原因。研究了成丝条件与蜘蛛丝分子结构及性能的关系在分析蜘蛛丝生物纺丝机制的基础上，研究了成丝过程中蜘蛛丝蛋白分子构象的变化规律，探索了成丝条件对蜘蛛丝分子结构的影响以及蜘蛛随着生存环境和成丝方式的不同对丝纤维性能的自动调控能力，并进一步分析了分子结构和蜘蛛丝力学性能间的关系。研究了蜘蛛丝结构的模化表达分析了影响蜘蛛丝力学性能的关键因素后，利用计算机对蜘蛛主腺体内丝蛋白含有的主要多肤链段的结构进于示了最优化设计，建立了蜘蛛丝皮芯层的聚集态结构模型和其拉伸变形的力学模型，分析了皮层、芯层的结构和应力—应变特征与蜘蛛丝纤维力学性能间的关系。研究了皮芯层的比例和性能特征对蜘蛛丝纤维拉伸断裂模式的作用，并建立了理论方程。更多还原

【Abstract】 Bio-macromolecular fibers were used in textile, medicine and biology et al. because of their intrinsic bio-functions. A lot of biomimetic and super biomimetic macromolecular fibers have been produced since the 20th 90’s and the study on biomaterials has focused on the new fiber with high strength and low density. Spider silk had excellent mechanical properties that were unique among natural and high performance synthetic fibers, so that a great number of research organizations and scholars were interested in the super biomaterials. Recently, the researchers overseas studied the structures and properties of spider silk. Meanwhile, with the development of biological technology, the artifical protein of spider silk was successfully produced with gene transplanting and the artifical spider silk was spun. However, this silk wasn’t industrially produced because of imperfect properties, complex process and high cost.The properties of fiber were determined by molecular structure and morphology from the view of material science. The fundamentally to understand the mechanisms of fiber properties was the study on the principal relationship between structures and properties. It was very important to investigate the structural mechanisms of spider silk properties and know the way to form the structure in order to transplant the mechanical properties of spider silk to artifical bio-macromolecular fibers.Araneus Ventrous spiders abroad distribute to everywhere in China. Some properties of three kinds of the spider silk fibers were studied which were dragline, framework and egg-case silks. These properties were mechanical properties, color and optical characteristics, density and deliquescent effect, thermal properties. On the basis of these, the mechanisms of excellent mechanical properties of the spider silk fibers were investigated on the following aspects.The first was the molecular foundations of mechanical properties of spidersilk fibers. The amino acid compositions were analyzed and compared with that of other species spider silks and Bymox fibroin. It was studied that how the amino acid compositions influenced on the molecular conformations and assignments. The molecular conformations of the spider silk fibers with different functions respectively were investigated by using Laser Raman spectrum and FTIR. The relationships were analyzed between the amino acid compositions, molecular structures and mechanical properties.The second was morphology and micro-shapes’ effects on the extra mechanical properties. The crystal and orientation of the spider silk were studied with X-ray diffraction. The configurations of these spider silk fibers were investigated by SEM images and their skin-core and fibril microstructures were found in the cross sections of processed fibers by physical or chemical methods. The reasons were analyzed, which these spider silk fibers with under 10% crystal regions had high strength and strains. The effects of skin-core structure on the mechanical properties were researched and the causes were analyzed that there were some differences in stress-strain behaviors of different functional spider silks.The third was the research on the relationships between the spinning conditions and the molecular structure, mechanical properties of the spider silk. On the basis of the analyzing of biological spinning mechanisms of spider silk, the molecular conformation change was studied in the spinning process and the effects of spinning conditions were investigated on the molecular structure. The active control on properties of spiders was studied with the varieties of environment and spinning way and the relationships were more analyzed between the structure and properties.Finally, the structural models of the spider silk were designed after understanding the key factors of mechanical properties of the fiber. The structures of some peptides contained in the major gland protein were optimized and two models were established, the first was skin-core morphology structure, second was the tensile mechan更多还原