劣化石刻表层生物矿化加固材料的探索性研究

Study on application of biomimetic materials to the consolidation of weathering carved stone

许多濒危石质文物表层劣化现象严重。但是,以往使用的表层加固材料很难令人满意,探索新的疏松岩石表层加固材料已是当务之急。由于天然生物矿化物耐候性优越,与基底岩石相容性良好,具有较好的加固作用,本工作依据生物矿化的原理,以不同生物大分子溶液作为有机模板,分别控制草酸钙、磷灰石和碳酸钙过饱和溶液于室温下在疏松岩石仿制样品的表层及孔隙内结晶生长。通过抗压强度、表面硬度和耐水浸泡等试验进行了加固效果评价,以考察仿生物矿化材料对含钙疏松岩石的加固能力。实验结果表明,仿生合成的生物矿化材料均具有一定的加固效果,其中以磷灰石仿生矿化材料的加固强度最大,以硫酸软骨素为模板的加固效果为佳。并且,在考察的3种加固方式中,以"直接混合"的加固强度更好,以"表面渗透"的耐水浸泡能力更强。本工作为开发濒危石质文物表层加固材料提供了新的思路。

Because of severe weathering, the surface of some of historic stones are in great danger. The surface - protective materials used in the past do not meet the requirements of conservators. It is a crucial task to develop new consolidating agents for soft stone surfaces. Certain crude biomimetic materials have performed well in terms of the resistance to ageing and great compatibility to stone matrixes; thus they are suitable materials for consolidation of historic stones that are in danger due to weathering. In this research, solutions of various biomacromolecules were selected as controlling templates. Super- saturated solution of calcium oxalate, apatite and calcium carbonate were applied on replicas of weathering stone at room temperature. The crystallization of these salts on the stone surface and cracks was controlled and their consolidation performances were evaluated in terms of , anti - compressive strength, surface hardness and water resistance. The results showed that the biomimetic materials prepared by biomimetic methods can consolidate the replicas of weathering stone. Among the biomimetic materials investigated, the consolidation strength of apatite is the highest and the consolidation performance of chondroitin sulfate is the best. Furthermore, of the three consolidation methods, the greatest specimen strength was achieved by direct mixing, but the highest water resistance was obtained through surface penetration of the specimen. Stone consolidation by biomimetic approach represents a new category of consolidation.