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| Author(s): |
Saly Takeshita
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2015-11-27 |
| Examining board members: |
Ivaldo Pontes Jankowsky;
Osmar Jose Romeiro de Aguiar;
Ariel de Andrade;
Geraldo Bortoletto Junior;
Luiz Fernando de Moura
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| Advisor: | Ivaldo Pontes Jankowsky |
| Abstract | |
Besides conventional drying, the application of heat treatment at high temperatures is one of the processes employed to improve the stability of wood, however they require its own structure and equipment. Therefore, the purpose of this research is based on the application of the stabilizers treatments studies of wood material hygroscopicity reduction, using low temperatures (below 150°C) and that allows practical application in drying equipment used in the domestic industry. The aim of this study was to evaluate the effects of stabilizing treatments on the physical properties and chemical components of wood for its practical feasibility. The research was comprised for two steps, the first: a total of three species of hardwoods had been used: Cedrinho (Erisma uncinatum), Tachi preto (Tachigali myrmecophyla) e Itaúba amarela (Mezilaurus itauba). The characterization of this three species was made by anatomical description, using Optical Microscope and Scanning Electron Microscopy (SEM), the chemical composition analysis and the physical properties. Samples of the stabilizing treatment, initially, were dried in a conventional kiln dryer and then the stabilizing treatment was applied in an autoclave at 90°C (24 e 96h) e 120°C (2h e 8h). Next, the hygroscopic conditioning were conducted (adsorption and desorption) in relative humidity (RH) of 30, 60 and 90% for evaluation of hygroscopic potential and dimensional changes. In the second stage, from the results obtained in the first step, it was possible to apply the treatment itself, the industrial scale pilot, using a conventional kiln dryer (90°C for 24 hours); and laboratory scale (90°C for 24 and 96 hours) in a climate chamber simulating a conventional dryer. For the pilot treatment, the availability of raw materials in the company was taken into account and focusing on the concurrent work between laboratory and industrial application, the selected specie was Cumarú (Dipterix sp), considered by the industry as one of the most problematic and, therefore a priority species to receive a treatment that can help to reduce the dimensional change after drying. The main results allowed to observe that the stabilizing treatments in the way that were applied in this study, did not cause changes in the chemical composition and when performed in an environment with high relative humidity, show no significant reduction of hygroscopicity and dimensional variation in most of conditionings. From the implementation of pilot treatment was observed that adopting the control of relative humidity, both in the beginning and the end of the process, is possible to reduce hygroscopic potential of wood by applying stabilizers treatments. (AU) | |
| FAPESP's process: | 12/15581-6 - Stabilizing treatments application after conventional drying to reduce the potential hygroscopic of wood |
| Grantee: | Saly Takeshita |
| Support Opportunities: | Scholarships in Brazil - Doctorate |