Structural changes and enhanced properties of bamboo fibers by controlled pyrolysis

Abstract

Bamboo has low-cost, fast-growing, good mechanical properties, and its cultivation results in environmental benefits such as CO2 sequestration and preservation of native forests, in addition to being an excellent source for natural fibers. Bamboo fiber presents high mechanical performance, which can be further improved by chemical or physical treatments. Controlled pyrolysis is an important treatment for modifying natural fibers, generating materials with different properties. In the present study, bamboo fibers from the species Dendrocalamus asper were subjected to controlled pyrolysis at 160, 400, and 800 °C and their morphological, thermal, and electric properties were evaluated by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, molecular absorption test, and electrochemical impedance spectroscopy. Controlled pyrolysis at 160 °C caused few changes to the structure and properties of the bamboo fiber. However, thermal stability, crystalline structure, and fiber morphology were strongly affected during pyrolysis at 400 and 800 °C. A resistive electric behavior was also verified in the fiber pyrolyzed at 800 °C, while for the other treated fibers, a capacitive electric behavior was verified. The controlled pyrolysis of bamboo fibers proved to be viable for producing new fibers with different properties.