Protection of Marble using Biodegradable Polymers in Historical Buildings

Project No


Supported by

Scientific and Technical Research Council of Turkey (TÜBİTAK)

Director of the Project

Prof. Dr. Hasan Böke


Assoc.Dr. Funda Tıhmınlıoğlu, Prof.Dr. Başak İpekoğlu, Assist.Prof.Dr. Aysun Çakan Sofuoğlu, Res.Assist. Yılmaz Ocak

Project Budget

78600 YTL

Project Term

24 months (July 2005 – July 2007)

The decay of historic buildings and monuments constructed by marble has been accelerated to a great extent in the past century due to air pollution. Sulphur dioxide is mainly responsible for this decay by producing gypsum. Gypsum, being a relatively soluble substance develops crust at rain – sheltered surfaces and accelerates erosion at the areas exposed to rain. Eventually, all these lead to significant deformations in the appearance and structure of marble.

In the recent past, calcareous stone – SO2 reaction has been the subject of many investigations, ranging from  field studies to laboratory investigations using enriched SO2 atmosphere and rather simple matrices. Aiming to cure the deterioration, various types of synthetic polymeric coatings which isolate marble from atmospheric SO2 have been used both in laboratory conditions and in situ for preventing gypsum formation on calcareous stones. Such coatings, particularly when applied upon rain-protected surfaces, have often been found more harmful than if the marble was left untreated.

Although synthetic polymers have been used previously by many researchers to protect the marble from the surrounding environment, to our knowledge, nobody has yet been used biodegradable polymer for this purpose.  Biodegradable polymers have attracted considerable recent interest for a variety of applications, such as medicine, and food packaging. Since these polymers are reversible and degrade by time, it will allow new treatment of the material to be protected.  These properties comply with the generally accepted conservation principles

Based upon certain earlier work, it was reported that some of these biopolymers (such as polylactide, polyhydroxybutyrate, etc) have shown moisture barrier properties. Therefore, by using these types of polymers on the marble surface, we expect to see reducing water and water vapour transmission to the stone and reducing formation of gypsum on the surface. In this project, it is aimed to use some biodegradable polymers (Polylactide, polyhydroxybutytrate, chitosan  and/or  their blends) for the protection of marble which will prevent gypsum formation on its surface. The effects of polymer type and polymer coating thickness on the mineralogical and surface properties of the marble will be investigated by using reaction chamber. The reaction products will be determined by using X-Ray diffraction, FTIR, ion chromotagrapy and flame photometry. The change of the surface morphologies of the marble plates will be determined using SEM and AFM.