石质文物表面憎水性化学保护的副作用研究

根据最小干预和不影响文物原貌的原则,使用表面化学防护和化学加固等保护材料被认为是保护石质文物的有效方法。目前,已试用于石质文物表面保护的化学材料主要是有机硅等有机化合物。这些有机材料能起到一定的防水和加固作用,但是也潜在不少问题,一些可能的危害目前还没有引起人们足够的重视。本工作以通用有机硅类防水加固剂为表面保护材料,以砂岩、凝灰岩、白云岩、大理岩和花岗岩为保护对象,模拟各种破坏因素,包括干湿循环、盐结晶、冻融和加热等的作用和联合作用,研究了表面化学处理后岩石样品在模拟环境中的变化情况,发现破坏现象严重。其中,化学保护剂在石材表层产生的亲水/憎水界面导致石材受某些应力的加速破坏是重要原因。上述研究结果提示,在石质文物的保护中应慎重使用憎水性表面化学保护剂。

The harmful effects of surface chemical protection of historic stones

In abiding by the principles of minimum intervention when preserving historic relics,the use of surface chemical materials to protect historic stones has been considered as an effective method.Presently,the primary materials used in the protection of historic stones are organic silicon compound,fluorine containing polymer,and etc.These organic materials have a certain level of effectiveness in protecting the historic stones,but there are also some problems.Currently,there are some possible threats that have yet to capture serious attention.To study the condition of stone materials after surface treatment with protective chemicals,Alkoxysilanes was used on various types of stone materials such as sandstone,tuff,dolomite and marble,in simulated environments with destructive elements such as moisture cycles,salt crystal,frost and fusion.Damage on the stones was discovered.The damage is due to an antinomy.The hydrophilic nature of stone and the waterresistance of organic conservation films create stress that damages the stones' surface.The research shows that conservators must be careful when using organic protectants that are waterresistant when treating historic stones.