Abstract:
This investigation demonstrated the transformation of valueless banana pseudostem into a high value cellulose nanocrystal (BCN) by chemical methods and the development and characterization of a novel BCN epoxy resin composite. BCN were extracted in a three-step procedure; hydrolysis with 2 wt% NaOH for 4 h at 100oC and dialysis leads to the gradual reduction of lignin and the production of holocellulose. Bleaching at 50oC for 2 h with 7.2 wt% H2O2 and 4wt% NaOH and dialysis remove colouring
matters; hydrolysis with 64 wt% H2SO4 for 2 h at 45oC under vigorous stirring allowed obtaining BCN as an aqueous suspension. Sonication and
freeze drying yielded BCN. Whatman filter paper cellulose nanocrystals
(FCN) were prepared as a control for the comparison purpose. Chemical
analysis of BCN showed 64 wt% cellulose and 0.1 wt% lignin and 6.8 wt% ash contents. BCN were assessed by morphological investigations (optical
and scanning electron microscopy) as well as physico-chemical methods
(wide angle X-ray scattering for crystallinity index) and by Fourier transform infrared spectroscopy. Absence of peaks in 1509-1609 cm-1 region of FTIR spectra indicated lignin has removed and the disappearance of 1734 cm-1 peak provided evidence for the removal hemicellulose by the extraction process. XRD results indicate that the crystallinity has increased in the BCN. The reinforcing potential was investigated by incorporating BCN in a
thermosetting epoxy resin matrixin different ratios of 10-80 wt%. Shore
hardness measurements evidenced that all composites were stiffer, stronger, and less extensible than the corresponding neat polymer. The reinforcing effect increased with increasing BCN content. The SEM images presented secreted indicating the bio-functional properties.The results reported support the repeatability and the effectiveness of the procedure performed.
