Vol.08. Nos.1 - 2 (2009) pp.31-42
Title:

Mechanical, thermal and microstructural analyses of Dendrocalamus giganteus.

Authors:D'Almeida, ALFS; Maurício, M.H.P; D'Almeida, J.R.M

Abstract:The flexural mechanical behaviour of Dendrocalamus giganteus strips machined from three different regions along the culmsí height was analyzed as a function of the aging time in distilled water. For the as-machined strips, the flexural properties did not vary with the culmsí height. For the aged specimens the modulus of rupture decreased in relationship to the values of the unaged specimens and also decreased from the bottom to the top of the culms. The flexural modulus also decreased when unaged and aged specimens are compared, but did not vary within the same immersion time with the specimensí position along the culms. Optical microscopy and digital image processing techniques were employed to evaluate the variations of the microstructure along the culms. A mosaic technique was used to analyze the entire cross section enabling quantitative measurements of a large number of fibers. The results showed that main structural parameter, such as the number of fibers per area, was statistically identical along the culms. The shape of the fibers was, however, dependent on the position, with more elongated fibers positioned at the top of the culms. The thermal behaviour of D. giganteus was also determined by thermogravimetric analysis. An activation energy of 166 kJ/mol was obtained for the thermal degradation process, which occurred on a single stage, and begins at 280.1∫C.

Keywords:bamboos; image processing; mechanical properties; plant fibres; stems; thermal degradation

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