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Influência da preparação da amostra nos resultados da análise da composição química da madeira
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Resumo(s)
The main purpose of this study was to assess the impact of the preparation of the
samples in the results obtained in the chemical composition analysis of wood. This was
studied for Maritime Pine (Pinus pinaster Aiton) and Eucalyptus (Eucalyptus globulus) in
samples with different extractives content.
The yield in different particle sizes after milling was shown to be influenced by the
size and morphology of sieve meshes and level of extractives. The yield in the 40/60 mesh
fraction was always relatively low (<22%)
Extractives content increased from the most coarse to the finer particle sizes.
However, the "particle size" effect was shown to be determined mostly by differences in the
chemical composition, as shown by the analysis performed after re-grinding.
The methods of extraction, Soxhlet and Soxtec, were shown to have similar
accuracies.
Regarding the content of Klason lignin, the two coarsest samples showed the
occurrence of an incomplete hydrolysis, as evidenced by infrared analysis. The sample of
finer particle size, in the case of eucalyptus, had higher lignin content than the other
samples.
The content of lignin obtained through analytical pyrolysis showed lower values than
those obtained by the Klason method.
Descrição
Mestrado em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia
Palavras-chave
pinus pinaster eucalyptus globulus granulometria análise química lenhina extractivos particle size chemical analysis lignin extractives