Evaluation of the effects of gamma radiation on thermal properties of wood species used in Brazilian artistic and cultural heritage
The wood is considered a natural composite of extreme complexity, mainly composed of cellulose, lignin, hemicellulose (polyposis), and extractives. Its composition encourages biological attacks from different species. In this context, several techniques have been studied and applied for disinfecting and decontaminating wood-made works of art and cultural heritage objects, which have been damaged by fungi, bacteria, and insects. Gamma radiation has been studied as an alternative to chemical methodologies for this purpose. By this way, the aim of this article is to illustrate the effect of gamma radiation on some physicochemical properties of Pinnus patula, Pinnus cunninghamia, Cedrella fissillis, and Ocotea porosa wood species. The irradiation has shown itself to be a fast and efficient process to eliminate infestations by both insects and microorganisms and no quarantine is required because of the no generation of toxic residues. On the other hand, this process does not protect the irradiated material from re-infestations or re-contamination. In this study, relatively high gamma radiation doses were applied up to 100 kGy so that radiation effects, which are cumulative, could be retrieved by means of thermal properties. The results have shown that gamma radiation, in the studied dose range, does not promote meaningful alterations on the evaluated properties, which allows that artifacts be irradiated multiple times, even if a re-infestation occurs.
KeywordsGamma radiation Wood Thermal properties Cultural heritage
The authors thank Mrs. Marcia Mathias Rizzo and Mr. Danilo Bras dos Santos by suggesting the wood species; Mr. Alex Correia dos Santos by helping during TG tests; Ms. Yasko Kodama and Mr. Paulo de Souza Santos by the 60-cobalt irradiation procedure; and Brazilian National Commission for Nuclear Energy (CNEN) by funding this research (Grant no. 01341.001411/2008-80).
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