Evaluation of the effects of gamma radiation on thermal properties of wood species used in Brazilian artistic and cultural heritage Lucio Cesar Severiano • Francisco Antonio Rocco Lahr • Marcelo Augusto Gonc ¸alves Bardi • Luci Diva Brocardo Machado CBRATEC7 Conference Special Issue Ó Akade ´miai Kiado ´, Budapest, Hungary 2011 Abstract 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, Ced- rella fissillis, and Ocotea porosa wood species. The irra- diation 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 radi- ation 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. Keywords Gamma radiation Á Wood Á Thermal properties Á Cultural heritage Introduction Wood has strongly influenced cultures throughout the centuries because of its easy manufacturing of furniture, sculptures, and pieces of art and artifacts found in ancient churches, such as paintings, frames, decorations, sculp- tures, furniture, and so on. In Brazil, due to the variety of wood species, the preliminary study about mechanical characteristics of wood has started at the beginning of the century. The results obtained at the time were used to study the properties of some species. By means of the collected materials, it was possible to establish peculiar strength limits of species as well as evaluate relative values of their properties based on the required application [1]. According to Mano [2], wood is considered a natural composite of extreme complexity, where the structural elements are represented by cellulose and lignin fibers. Its ultra-structure and chemical composition as well as its physical and mechanical properties significantly differ among species, among trees of the same species, and even among different parts of the same tree [3]. As described by Lara [3], a large number of Brazilian wooden cultural heritages is undergoing a deterioration process and so requires methodologies to its protection against weathering and biological attacks. With regard to Cappitelli [4], in the last decades growing concerns on the use of chemical compounds has resulted in an in-depth evaluation of the effects of pesticides on the human health L. C. Severiano Á M. A. G. Bardi Á L. D. B. Machado (&) Instituto de Pesquisas Energe ´ticas e Nucleares/Comissa ˜o Nacional de Energia Nuclear (IPEN/CNEN-SP), Centro de Tecnologia das Radiac ¸o ˜es, Av. Prof. Lineu Prestes, n. 2242, Cidade Universita ´ria, Sa ˜o Paulo, SP 05508-000, Brazil e-mail: lmachado@ipen.br F. A. R. Lahr Laborato ´rio de Madeiras e Estruturas de Madeiras, Universidade de Sa ˜o Paulo (USP), Av. Trabalhador Sa ˜o-Carlense, n. 400, Sa ˜o Carlos, SP 13566-590, Brazil 123 J Therm Anal Calorim (2011) 106:783–786 DOI 10.1007/s10973-011-1840-y