基于生物矿化的石质文物仿生保护

发布时间：2018-03-05 22:36

本文选题：石质文物　切入点：生物矿化　出处：《浙江大学》2007年博士论文　论文类型：学位论文

【摘要】： 暴露在野外的众多大型石质古迹，由于自然因素的风化作用和人为因素的破坏，许多表面劣化现象严重。如不采取有效措施，许多珍贵的实物记录将不复存在。但是，目前所使用的保护材料几乎都不能完全满足保护者的要求。所以，研制性能良好的石质文物保护功能材料已成为文物保护研究领域的迫切任务之一。本论文综述了石质文物风化的特征和条件，以及国内外相关保护材料的性能、保护效果和存在的问题。在天然生成的草酸钙生物矿化保护膜的启示下，，根据“生物矿化”原理，提出了采用“仿生”方法对石质文物进行保护的新思路，仿生合成了一系列无机生物矿化保护材料。通过研究实验，获得了如下的结果： (1)选用目前应用广泛的有机硅类保护剂作为表面防护材料，以常见的文物石材：砂岩、凝灰岩、白云岩、大理岩和花岗岩为保护对象，试验研究了文物的主要破坏因素，包括干湿循环、盐结晶、冻融和加热等作用，以及它们的联合作用，证实石质文物表面憎水性化学保护有可能起不到保护作用，甚至会产生严重的破坏。破坏的主要原因是被保护表层的憎水性和岩石基底的亲水性引起的化学物理性质的差异和界面应力的加剧。并提出解决这一矛盾的有效途径之一是开发非严格憎水且具有耐酸、耐污等效果的与石材相容良好的保护材料，如生物矿化材料。 (2)试验研究了石材的表面预处理方法，包括有机溶剂的清洗，以及生物性大分子的表面功能化。通过表面能的表征，确定了最佳的石材表面预处理条件，即使石材的表面最佳功能化。选用一种生物粘多糖——硫酸软骨素作为有机模板，以亚稳态的草酸钙过饱和溶液为前驱液，在大理岩石表面仿生合成了草酸钙表面防护材料。通过设计正交试验，考察了仿生合成的各个因素的影响程度，以及较佳的合成条件。仿生合成的影响因素的影响程度为：有机模板的影响＞成矿离子前驱液的影响＞石材表面预清洁方式的影响＞保护膜层数的影响，较佳的制备条件是：石材表面用乙醇预清洁，较浓浓度的有机模板溶液使之表面功能化，过滤的草酸钙过饱和溶液作前驱液，多层制膜。分别采用XRD、SEM和AFM分析表征了材料的物相组成及微观形貌，证明石材表面的防护材料为一层约100 nm厚的薄片状的一水草酸钙晶体，并解释了材料的合成机理。通过憎水性、耐酸性、耐污性、耐老化性和透气性的测试，表明该材料亲水、防酸、防污、透气，且耐老化性能良好。在仿生合成草酸钙表面防护材料的基础上，进一步拓宽了仿生合成生物矿化保护材料的研究范围，包括草酸钙系列、磷灰石系列和碳酸钙系列。采用SEM表征了材料的微观形貌。以耐酸性、耐污性和耐老化性表征了各系列材料的表面防护效果，结果表明几种考察的材料均有不同程度的防护效果，尤以草酸钙为佳，其耐酸性达到pH≈0.8，耐污性≈2级，耐老化性及透气性能良好。对石质文物表面进行仿生防护，将生物矿化作用引入石质文物保护研究领域，提出采用“仿生”的方法保护石质文物的新思路，试验证明方法可行。 (3)考虑到濒危石质文物表面结构疏松，本工作进一步探讨了仿生矿化保护材料的加固性能。借鉴岩土工程学的理论，用颗粒碳酸钙和粉末碳酸钙仿制了劣化的岩石。将仿生合成的一系列表面保护材料应用到仿制的样品上，考察了它们的抗压强度和抗水浸泡分解能力。结果表明，仿生矿化保护材料的加固效果良好，抗压强度和抗水浸泡能力都得到了较大的提高。加固效果最佳的是磷灰石材料，加固后，仿制样品的抗压强度可提高3～4倍，并可抗水浸泡6个月以上。 (4)在实验研究结果的基础上，选择草酸钙和其它常用的有机保护材料，在洛阳龙门石窟做了现场保护对比实验，初期效果显示，仿生矿化材料的保护效果良好，显示了仿生矿化保护材料在石质文物保护领域具有良好的应用前景。总之，本工作证实了有机憎水性保护材料的副作用，研制出系列仿生矿化保护材料，检测表明它们具有较好的表面防护效果和表层加固性能，并且制作工艺简便。文献检索表明，目前尚未发现有类似的研究报道。这些成果对于发展新型石质文物保护材料具有重要的现实意义，同时也拓宽了生物矿化材料研究的领域。
[Abstract]:Exposure in the wild many large stone monuments, due to natural weathering factors and man-made destruction, many surface deterioration phenomenon is serious. If we do not take effective measures, many valuable records will not exist. However, the protection materials used at present almost all can not fully meet the requirements of the protector. So, development the good performance of the stone relics protection function materials has become one of the urgent task of research in the field of cultural relics protection.
This paper summarizes the characteristics and conditions of weathering, as well as the domestic and foreign related protection material performance, protection effect and existing problems. In the natural biomineralization of calcium oxalate protective film of enlightenment, according to the principle of biomineralization. Put forward the new idea of using "bionic" method to stone conservation, a series of inorganic biomimetic protective materials by the biomimetic synthesis.
Through the research experiment, the following results are obtained.
(1) the protection of organosilicone agent widely used as coating materials, the common cultural relics: stone sandstone, tuff, dolomite, marble and granite as the object of protection, studied the main destructive factors of cultural relics, including the dry wet cycle, salt crystallization, freezing thawing and heating effects, and their combined effects the confirmed stone relics of hydrophobic chemical protection may have no protection, even will cause serious damage. The main reasons for the damage is the difference of chemical physical properties of hydrophilic protected surface hydrophobicity and rock substrate caused by the interfacial stress and increase. And put forward the effective way of to solve this contradiction is the development of non strict water repellent and has acid resistance, stain resistance and other effects of the compatibility of protective material with good stone, such as bio mineralization material.
(2) the surface pretreatment methods of stone, including cleaning of organic solvents and surface functionalization of biological macromolecules, were studied experimentally. The best pretreatment conditions for stone surface were determined by surface energy characterization, even if the surface of stone was best functionalized.
A kind of biological mucopolysaccharide, chondroitin sulfate as the organic template, calcium oxalate metastable supersaturated solution as precursor, the calcium oxalate surface protection material synthesis in Dali rock surface bionic. Through orthogonal experiment, influence degree of various factors of the biomimetic synthesis, and the synthesis conditions of better effect. Biomimetic synthesis factors for the effect of organic template > > effect of ion liquid precursor effects, forming the stone surface pre clean way of protective film layers, the better preparation conditions is: ethanol pre clean with the stone surface, surface functional organic template concentration solution is made of oxalic acid calcium filtering supersaturated solution as precursor, multilayer film.
Using XRD, SEM and AFM analysis to characterize the material phase composition and microstructure, proof of the stone surface protection material for calcium oxalate monohydrate layer about 100 nm thick thin, the synthesis mechanism of material and explanation. Through the hydrophobicity, acid resistance, stain resistance, aging resistance and the air permeability test showed that the hydrophilic material, anti acid, anti fouling, breathable, and aging resistant performance is good.
Based on the biomimetic synthesis of calcium oxalate surface protection materials, to further expand the biomimetic synthesis of biomimetic protective materials research, including calcium oxalate, calcium carbonate and apatite series series was characterized by SEM. The micro morphology of the materials. The acid resistance, stain resistance and aging resistance to characterize the surface protective effect of the series the results show that some of the material has protective effect in different degree, preferably in the calcium oxalate, the acid reached pH = 0.8 ~ 2, pollution resistance, aging resistance and good air permeability.
Bionic protection is applied to the surface of stone cultural relics, and biological mineralization is introduced into the research field of stone cultural relic protection. A new idea of "bionic" method for protecting stone cultural relics is put forward. The experiment proves that the method is feasible.
(3) taking into account the endangered stone cultural relics surface loose structure, this work further explores the reinforcement performance of biomimetic protective materials. From the geotechnical engineering theory, using granular calcium carbonate and calcium carbonate powder imitation of the deterioration of the rock. The biomimetic synthesis of a series of surface protective material applied to the imitation of the sample, study the compressive strength and resistance to their water soaking ability. The results show that the reinforcement effect of biomimetic protective materials, compressive strength and anti water ability have been greatly improved. The best reinforcement effect is apatite stone material, after reinforcement, the compressive strength of imitation samples can be increased by 3~4 times, and can resist soaked in water for more than 6 months.
(4) on the basis of experiment, selection of calcium oxalate and other common organic materials, the protection test in Luoyang Longmen Grottoes, the initial results show that the protective effect of biomimetic materials, shows the biomimetic protective materials has a good application prospect in the field of rock mass cultural relics protection.
In conclusion, this work confirms the organic hydrophobic protective material for side effects, developed a series of biomimetic protective materials, testing showed that they have good surface protection effect and surface strengthening performance, and simple manufacturing technology. A literature search shows that has not yet found a similar study. These results have important practical significance for the the development of new materials of stone cultural relics protection, but also broaden the research field of biomimetic materials.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2007
【分类号】：K854.3

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