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Long-term protection efficiency of biodegradable polymer treatments on limestone için kapak resmi
Long-term protection efficiency of biodegradable polymer treatments on limestone
Long-term protection efficiency of biodegradable polymer treatments on limestone
Kaplan, Zişan, author.
Yazar Ek Girişi:
Fiziksel Tanımlama:
xii, 89 leaves: charts;+ 1 computer laser optical disc.
Synthetic polymers can be replaced by biodegradable ones as adhesive, water repellents and consolidants in stone conservation to preserve historic buildings from further deterioration. In this study, the long-term stabilities of two biodegradable polymers, polyhydroxybutyrate (PHB) and poly-l-lactide (PLA) and an acrylic polymer (Paraloid B72), which are commonly used in conservation works of artefacts, were evaluated on limestone through an UV lamp-weathering chamber. Chemical and morphological changes induced by accelerated weathering test were followed by Fourier Transform Infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) analysis. The protection efficiencies of the polymers were determined by following the changes in the color, capillary water absorption and static contact angle on the limestone surfaces in accordance with CEN standards developed by the European Committee of Standardization (CEN) for conservation of cultural property. PHB, PLA and Paraloid B72 coatings significantly increased hydrophobicity, decreased capillary water absorption and caused negligible change in the color of the limestone. All polymers showed chemical, physical and optical changes under accelerated weathering conditions. Paraloid B72 decomposed by the reduction of molecular weight, decomposition of ester group and formation of gamma lactones and hydro peroxides. PHB and PLA decomposed with formation of CO2 and hydro peroxide, hydrolysis of ester groups and reduction of the molecular weight. Chemical changes cause to etching, holes, voids, cracks and slight color differentiations on the coatings by chain scission, breaking of polymer bonds and formation of volatile gaseous products. Protection efficiencies of the PLA and PHB polymers almost same as that of the widely used acrylic polymer Paraloid B72. However, PLA and PHB seem to be promising polymers as protective agents due to their reversibility and biodegradability, low chromatic changes, good hydrophobic behavior and good stability to weathering in reducing the effects of outdoor exposure on limestone surfaces.
Yazar Ek Girişi:
Tek Biçim Eser Adı:
Thesis (Doctoral)--İzmir Institute of Technology: Architectural Restoration

İzmir Institute of Technology: Architectural Restoration--Thesis (Doctoral).
Elektronik Erişim:
Access to Electronic Versiyon.
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