New approach for extraction of cellulose from tucumã's endocarp and its structural characterization
| Autor: | C.G. da Silva, John Simonsen, S. M. de Souza, L.C.A. Rabelo, Danieli Silva de Souza Rabelo, Lizandro Manzato, Edgar A. Sanches, Luis André Morais Mariúba |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Rietveld refinement
Scanning electron microscope Organic Chemistry Analytical chemistry Mineralogy 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Analytical Chemistry Inorganic Chemistry Crystallinity chemistry.chemical_compound chemistry Thermal stability Crystallite Cellulose Fourier transform infrared spectroscopy 0210 nano-technology Thermal analysis Spectroscopy |
| Zdroj: | Journal of Molecular Structure. 1143:229-234 |
| ISSN: | 0022-2860 |
| DOI: | 10.1016/j.molstruc.2017.04.088 |
| Popis: | The recycling of plant wasted materials into useful products represents a green alternative to prevent environmental problems. Tucuma palm fruit ( Astrocaryum aculeatum Meyer) is widely used in Amazon region for food and crafts. Due to the large amount of wasted Tucuma’s endocarp, this work proposes a new approach for extraction of cellulose and its structural characterization. X-ray Diffraction (XRD), Rietveld Refinement, Scanning Electron Microscopy (SEM), Infrared-transform Fourier Spectroscopy (FTIR) and Thermal Analysis (TG/DSC) have been used for characterization of the extracted cellulose. XRD patterns of the in natura tucuma’s endocarp has showed a natural crystalline content embedded in a non-crystalline matrix. Nanocrystals of cellulose have been observed in the XRD pattern of the extracted cellulose, showing a good agreement with type II. Rietveld refinement allowed the cell parameters obtainment ( a = 8.43(1) A, b = 9.50(1) A, c = 9.39(3) A and γ = 118.43(4)°). Apparent average crystallite size and microstrain were, respectively, 20.0 A and 0.1%. Two different methods were applied for estimative of crystallinity percentage. In the first method the height ratio between the intensity of the crystalline peak and the total intensity after the subtraction of the non-crystalline content was applied, leading to 48.5%. The second approach was performed using the amorphous area and the total area of the (1 1 0) peak from the experimental diffractogram, leading to 31.5%. The difference in crystallinity percentage concerning these two used approaches may be explained due to the first method does not consider the broad peaks resulted from nanocrystals diffraction. FTIR spectroscopy has evidenced a cellulose type II structure. SEM images showed micrometric sized fibers with ranged thicknesses. However, a new morphology of spherical nanostructures was observed on the type II matrix fibers. Thermal analysis suggests that the extracted cellulose have low thermal stability, which resulted from poor ordered, packed chains. A large exothermic band was found in DSC curve and associated to the release of energy from the amorphous phase degradation. Thus, this work successfully extracted cellulose from tucuma’s endocarp and allowed its structural, morphological and thermal characterization. |
| Databáze: | OpenAIRE |
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