珍珠母堆垛微结构的力学性能和热稳定性  

Mechanical properties and thermal stability of stacked microstructure of nacre

作　　者：孙晋美[1] 郭万林[2] 

机构地区：[1]青岛理工大学琴岛学院机电系,青岛266106 [2]南京航空航天大学纳米科学研究所,南京210016

出　　处：《中国科学：物理学、力学、天文学》2010年第8期1044-1053,共10页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家重点基础研究发展计划(编号:2007CB936204);教育部创新团队(编号:705021;IRT0534);国家自然科学基金(批准号:10732040);江苏省自然科学基金(编号:BK2008042)资助项目

摘　　要：一直以来,软体动物贝壳内的珍珠母因为其由文石片和片间有机基质薄层堆垛而成的微结构及其卓越的力学行为而广受关注,但对贝壳珍珠母的多级结构,尤其是其中的两级有机基质结构的力学功能研究甚少.本文通过机械载荷和温度载荷组合来研究皱纹盘鲍(Haliotis Discus Hannai)贝壳内的珍珠母的结构和力学特性关联.发现文石片层间的有机基质的热解有效降低了珍珠母堆垛微结构的强度和韧性,并在250℃时使珍珠母的层叠堆垛结构完全崩溃,此时有机基质的热解量约为1.7wt%,仅为有机基质总量的40%.而力学性能试验比较发现,珍珠母堆垛微结构的热稳定远低于其基本组成单元——文石片纳米复合结构.另外,尽管有机基质薄层的黏着作用对珍珠母的力学性能具有积极意义,但珍珠母微结构本身的逐层交错堆垛设计机制是影响其刚度的决定性因素.Large amount of effort has been invested in nacre of mollusc shells because of its stacked microstructure with aragonite platelets and thin organic matrix interlayers and excellent mechanical properties. However, the contribution to the mechanical properties by the interplatelet and intraplatelet organic matrixs in nacre is poorly understood. In this work, the structure-mechanical property relationship of nacre from Haliotis discus hannai was studied by mechanical tests coupling with thermal loads. It is found the thermal decomposition of interplatelet organic matrix effectively decreases the strength and toughness of nacre and makes its layer-stacked microstructure destroyed completely at 250~C. However, at 250~C organic matrix of about 1.7 wt% is decomposed, which is only 40% of total organic matrix. And mechanical properties tests show that the thermal stability of the stacked microstructure of nacre is much worse than its primary element--the nanocomposite structure of aragonite platelet. Besides we propose that the structural design mechanism of layer-by-layer stacked form is the determinative factor of nacre stiffness, and the adhesives effect of organic matrix interlayers is also significant.

关 键 词：珍珠母 堆垛微结构 有机基质 力学性能 热稳定性 

分 类 号：Q6[生物学—生物物理学]