International Journal of Modern Engineering Research (IJMER) www.ijmer.com Vol. 2, Issue. 6, Nov-Dec. 2012 pp-4378-4382 ISSN: 2249-6645 www.ijmer.com 4378 | Page Ladislav Reinprecht, 1 Ján Iždinský, 2 1, 2 (Department of Mechanical Wood Technology, Technical University of Zvolen, Masarykova 24, Slovakia) ABSTRACT : The aim of this study was to determine retention and distribution of the polybuthylmethacrylate resin Solakryl BT-55 in conserved lime tree wood (Tilia cordata Mill.) using conventional method and gamma ray method working with radioisotope 241 Am. Conservation of sound lime tree samples 60 x 60 x 60 mm with known densities and density profiles in all three anatomical directions was performed with a 27.5 % toluene acrylic solution (Solakryl BT-55 diluted with toluene in a ratio of 1:1) in autoclave at 20 °C and 0.8 MPa for 5, 30 or 180 minutes. Total retentions of the acryl resin increased nonlinearly with prolongation of the impregnation process when densities in the oven dry state of conserved samples increased about 20.5 % (5 min), 25.5 % (30 min) or 30 % (180 min). The gamma ray distribution analyses of the acryl resin showed that lime tree wood had the best impregnability in the longitudinal direction. Differential retentions of the solid acrylic resin into samples varied from 0.15 to 0.20 g/cm 3 at distance of 5 mm from the axial surfaces, from 0.05 to 0.13 g/cm 3 at distance of 20 mm from the axial surfaces, and only from 0.02 to 0.11 g/cm 3 in the centre of samples (at distance of 30 mm). Penetrations of the acryl resin in the radial and tangential directions were negligible, unlike the longitudinal direction. Keywords: acryl resin, distribution, lime tree, radioisotope 241 Am, retention I. INTRODUCTION Generally, for improving the esthetical, physical and mechanical properties of wood and wooden artefacts are used conservation agents. Efficiency of various conservation processes with natural and synthetic agents depends on more factors related to (1) wood structure, e.g. species, permeability, moisture, geometry, range and degree of damaging by bacteria, fungi, insect, etc., (2) macro- and micro-distribution of the conservation agents in wood which depends on their properties and also on technological parameters of the conservation process, e.g. pressure and time, (3) physical and chemical properties of conservation agents, e.g. viscosity, surface tension, polarity, molecular weight, possibility for reactions with –OH groups of cellulose, etc. [1,2]. Distribution of acryl and other conservation agents in wood can be determined by destructive methods, e.g. on small drilled samples, cross-sections and micro-slides by a scanning electron microscope – SEM [3], and also by various non-destructive methods, e.g. by acoustic, thermographic, nuclear magnetic resonance or radiographic [4, 5, 6]. At analysis the penetration, retention and distribution of conservation agents in wooden objects, similar to estimation of moisture, adhesive, mechanical behavior, growth rings, knots, or defects caused by fungi and insect, The following stationary or mobile radiographic methods are usually applied [4, 7, 8, 9, 10, 11, 12, 13, 14, 15]: - Conventional X-ray radiography – one line scanning, - Gamma rays densitometry – one line scanning, - X-ray computer tomography scanning (2D and 3D, e.g. SRXTM), - γ-ray computer tomography scanning (2D and 3D), - scanning neutron radiography. The aim of this work was to evaluate the acryl resin “Solakryl BT-55” retention and distribution in lime tree wood in the longitudinal, radial and tangential directions after its pressure impregnation, using one line scanning gamma rays densitometry – the analyzer of density profiles. The density profiles of lime tree samples were monitored before and after conservation and from these profiles the acryl resin amount in defined distances from the external surfaces of conserved samples were computed. Used analyzer of density profiles is based on the measurement of the absorption coefficient attenuate of the gamma-radiation from the isotope 241 Am passing through tested material. More other researches preferred this isotope at testing the density and quality of wood and wooden composites [16, 17, 18, etc.]. II. MATERIAL AND METHODS 2.1 Lime tree wood Samples, 60 mm x 60 mm x 60 mm (longitudinal x radial x tangential), were prepared from one lime tree (Tilia cordata Mill.) sound board 1400 x 400 x 100 mm which was previously kiln dried and conditioned on approximately 12 % moisture content. Natural samples without knots or other inhomogeneities were then selected for the experiment. In the oven dry state were determined their total densities “ρ N (g/cm 3 )” and density profiles in three anatomical directions “ρ N-profile (g/cm 3 )”. 2.2 Acryl resin For the lime tree samples conservation was used commercial product Solakryl BT-55, which contains 55 % of the polybuthylmethacrylate (PBMA) and it is manufactured in the Lučební závody, Draslovka a.s. Kolín, Czech Republic. In the experiment was used a 27.5 % solution of the acryl resin. It means the Solakryl BT-55 was diluted with toluene in a weight ratio 1:1 (w/w). This resin is convenient for restoration works, e.g. for consolidation of wooden artefacts. Its basic chemical-physical properties by the technical sheet PND 47-701-93 are as follows: Mw = 40.103 g/mol; ρ = 900 kg/m 3 ; Tg = 45 °C. 2.3 Conservation process Conservation of the lime tree samples with Solakryl BT-55 was performed in the Dreyer-Holand- Acryl Resin Distribution In Lime Tree Wood Determined By 241Am Analyser Of Density Profiles