Effect of chemical modifications on the thermal stability and degradation of banana fiber and banana fiber‐reinforced phenol formaldehyde composites

Banana fiber has been modified by treatments with sodium hydroxide, silanes, cyanoethylation, heat treatment, and latex treatment and the thermal degradation behavior of the fiber was analyzed by thermogravimetry and derivative thermogravimetry analysis. Both treated and untreated fibers showed two‐stage decomposition. All the treatments were found to increase the thermal stability of the fiber due to the physical and chemical changes induced by the treatments. The thermal degradation of treated and untreated banana fiber‐reinforced phenol formaldehyde composites has also been analyzed. It was found that the thermal stability of the composites was much higher than that of fibers but they are less stable compared to neat PF resin matrix. Composite samples were found to have four‐stage degradation. The NaOH treated fiber‐reinforced composites have very good fiber/matrix adhesion and hence improvement in thermal stability is observed. Though both silane treatments increased the thermal stability of the composite the vinyl silane is found to be more effective. Heat treatment improves the crystallinity of the fiber and decreases the moisture content, hence an improved thermal stability. The latex treatment and cyanoethylation make the fiber surface hydrophobic, here also the composite is thermally more stable than untreated one. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008