Figure 1

SEM images of untreated sugar cane bagasse (A, B and C); (A) General view of the sample showing the fibers (mainly); (B and C) higher magnification image of fiber surface; SEM images of sugar cane bagasse pretreated with SO₂ (190°C/5 min) (D, E and F); (D) General view of the sample showing the fibers (mainly); (E) higher magnification image of fiber surface (arrows in the D image); (F) higher magnification image of fiber surface extremity; SEM images of the bagasse pretreated with CO₂ (205°C/15 min) (G, H and I); (G) General view of the sample showing the fibers (mainly); (H) and (I) higher magnification images of fiber surface (arrows in the G image).