Resumo

SOTOMAYOR-CASTELLANOS, J.R.  e  AVILA-CALDERON, L.E.A.. Impregnation with boron salts of the wood of Spathodea campanulata P. Beauv, Fraxinus americana L. and Albizia plurijuga (Standl.) Britton & Rose. Ultrasound evaluation of wave velocity and dynamic modulus. RIIIT. Rev. int. investig. innov. tecnol. [online]. 2020, vol.8, n.45, pp.40-50.  Epub 05-Fev-2021. ISSN 2007-9753.

The protection of wood with boron salts affects the physical and mechanical characteristics of the wood according to the type of treatment applied and the species. The objective of the research was to compare the density, ultrasound speed and dynamic modulus of 40 small-sized specimens of wood from Spathodea campanulata, Fraxinus americana and Albizia plurijuga that were impregnated with boron salts in concentrations of 1 %, 2 % and 3 %. In order to achieve this; the densities, wave velocities and dynamic modules were calculated by ultrasound before and after the treatment. Retentions were calculated after treatment. The moisture content of the untreated wood of S. campanulata was 8 %, that of F. americana 10 % and that of A. plurijuga 12 %. The average retention of the three groups of specimens with concentrations of 1 %, 2 % and 3 % were for S. campanulata, R = 3,2 kg m-3, for F. americana R = 2,6 kg m-3 and for A. plurijuga R = 1,9 kg m-3. The average densities for S. campanulata were 351 kg m-3, F. americana 652 kg m-3 and for A. plurijuga 838 kg m-3. After treatment, wood densities decreased on average 0,6 % for S. campanulata and 0,2 % for A. plurijuga. For F. americana no differences are observed. As a treatment effect, the wave velocities decreased for S. campanulata -3,6 %, for F. americana -11,8 % and for A. plurijuga -5,1 %. The impregnated process with the cold-client bath method reduced the dynamic modules in particular to each species. For S. campanulata the reduction reached an average of -6,4 %; for F. americana the decrease was -22 % and for A. plurijuga it was -9 %. Densities correlate well with wave speeds with coefficients of determination of R2 = 0,69 before treatment and R2 = 0,55 after treatment. Densities explain the variation of the dynamic modules with an R2 = 0,88 before the treatment and with an R2 = 0,80 for after the treatment. With the experimental strategy, the retention capacity of boron salts of the mentioned wood was determined. In addition, the treatment effect on densities, wave speeds and dynamic modules were evaluated. The areas of the industry where the results of the research are applicable are in the manufacture of building components for furniture and in the elaboration of structural elements for construction.

Palavras-chave : dynamic modulus; retention; wave speed; wood density.

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