Morphological, physical, chemical, and thermal decomposition properties of air-heat-treated balsa fruit fibers at different temperatures

초록

This study was conducted to investigate the effect of air heat treatment on the morphological, physical, chemical, and thermal decomposition properties of balsa fruit fibers (BFF). BFF were heat-treated in air at 100 celcius, 200 celcius, 240 celcius, 280 celcius, 300 celcius, 320 celcius, and 340 celcius. Color changes, weight loss, and moisture adsorption were also examined. The color of BFF was light brown below 200 celcius, brown at 240 celcius, dark brown at 280 celcius, and black from 320 celcius. The total color change (& UDelta;E*) of BFF increased rapidly until 280 celcius and became from 280 celcius constant until 400 celcius. The microfibrils in the fibers were observed below 240 celcius and disappeared at 280 celcius, and the fibers heat-treated above 280 celcius showed an amorphous-like cell wall. The fibers below 240 celcius showed a straight form with a smooth surface, whereas the fibers at 240 and 280 celcius showed an uneven form with lumps on their surface due to melted wax. With increasing temperature, the weight and width of the fibers decreased. The vapor adsorption property of the BFF increased with increasing treatment temperatures. X-ray diffractograms of BFF showed cellulose I crystalline structure until 320 celcius, which changed to amorphous at 340 celcius. Holocellulose, & alpha;-cellulose, and hemicellulose were detected in fibers below 240 celcius but not in samples treated at 280 celcius. The wax content of the BFF decreased as temperatures increased. FT-IR spectra showed the peaks of plant wax and carbohydrate compounds in BFF until 320 celcius and the peaks of lignin at all temperatures. The thermal decomposition properties of BFF noticeably changed after heat treatment above 240 celcius.

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