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Characterization of Tannin-Based Resins from the Barks of <i>Ficus platyphylla</i>and of <i>Vitellaria paradoxa</i>: Composites’ Performances and Applications

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Materials Sciences and Applications 2017年第12期8卷 899-917页

作者： Richard Ntenga frederic djoda pagore Antonio Pizzi Etienne Mfoumou Louis-Max Ayina Ohandja Laboratoire de Mécanique et Productique (LMP) UFD SI Université de Douala Douala Cameroun Laboratoire d’Analyse Simulations et Essais (LASE) IUT Université de Ngaoundéré Ngaoundere Cameroun ENSTIB-LERMAB Nancy University 27 rue du Merle Blanc Epinal France Department of Physics King Abdulaziz University Jeddah KSA Applied Research & Innovation Nova Scotia Community College Dartmouth Canada Laboratory of Materials Mechanics Structures and Integrated Manufacturing National Advanced School of Engineering University of Yaoundé 1 Yaoundé Cameroon

This work investigates the physico-chemical and mechanical properties of tannins extracted from wood for composite materials manufacturing. Sustainable knowledge (in terms of physico-chemical properties and behaviours) of the material is needed to further enhance its applications. The condensed tannins extracted from the Bark of Ficus platyphylla (BFP) and the Bark of Vitellaria paradoxa (BVP) were analyzed using Matrix Assisted Laser Desorption/Ionization Time-Of-Flight (MALDI-TOF), Mass Spectroscopy and Attenuated Total Reflectance Fourier Transform Mid-InfraRed (ATR-FT MIR) spectra in the ranges 1800 cm-1 and 600 cm-1, as well as using CP MAS 13C-NMR. It was found that, these two tannins are procyanidin/prodelphinidin and made up of catechin/epicatechin, gallocatechin/epigallocatechin units, fisetinidin, galloyl and carbohydrates residues. Furthermore, BFP and BVP tannin bonded particleboard densities lie in the range recommended by NF EN 326-1994 standard. The resins also yielded good internal bond strength results of the panels, above relevant international standard specifications minimum requirements for interior-grade panels. The Transmission Electron Microscopy with Energy Dispersive X-ray Spectroscopy Analysis (TEM/ EDXA) are showing the ultrastructure and reveal that most of the resin material appears to be in an amorphous phase mainly composed of carbon/oxygen with small amounts of K, Ca and Mg. These particles have a very irregular morphology.

关键词： Wood Condensed Tannins Fibre/Matrix Bond Mechanical Properties Active Correlated Transmission Electron Microscopy (ACTEM) Matrix Assisted Laser Desorption/Ionization Time-Of-Flight (MALDI-TOF)

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Influence of Solvent onto Chemical Extraction of America-Type Coconut (Coco nucifera L.) Fbers: Analysis of Physicochemical, Mechanical and Morphological Properties

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Journal of Textile Science and Technology 2024年第3期10卷 64-81页

作者： Delphine Korgai Gandai Zara Haman djoda pagore frederic Memtine Ndong Augustin Abdourhamane Nsangou Niraka Blaise Hambate Gomdje Valery National Advanced School of Engineering of Maroua University of Maroua Maroua Cameroon School of Chemical Engineering and Mineral Industries University of Ngaoundere Ngaoundere Cameroon Department of Mechanical Engineering ENSET University of Douala Douala Cameroon

In this study, the natural fibers from Coconuts of the species Coco nucifera L. were Chemically extracted in different solvents such as sodium hydroxide (SH), acetone (AC) and sodium hydroxide-acetone (SHA) for their applications in the textile industries. Structural, morphological and physico-mechanical characterizations such as X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanned electron microscopy (SEM), measurements of density, Young’s modulus, water absorption rate and humidity were evaluated. The XRD and FTIR results show that Coco nucifera L. fibers contains type I cellulose. Mechanical characterizations were also carried out. These results show that by varying the different solvents used, the physico-chemical, mechanical and morphological properties of the fibers change, which implies that the solvent has an influence on the properties of these fibers. The fibers extracted by the sodium hydroxide-acetone mixture have a linear density of 1.636, the percentage of water absorption is 62.428%, the percentage of moisture absorption 9.605% compared to other values in the literature shows that this solvent mixture improves the properties of coconut fibers which contain type I cellulose. The tensile stress is 0.013 GPa, the percentage strain is 49.836% and the Young’s modulus is 0.114 GPa as well as the percentage elongation show that these fibers are elasto-plastic. The values obtained mean that these fibers are suitable for use in textiles.

关键词： Chemical Extraction Cellulose Coco nucifera L. Fibers Elasto-Plastic Textiles

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Clay Materials for Ceramics Application from N’Djamena in the Chad Republic: Mineralogical, Physicochemical and Microstructural Characterization

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Journal of Materials Science and Chemical Engineering 2024年第2期12卷 31-48页

作者： Ndjolba Madjihingam djoda pagore Jacques Richard Mache Bebbata Warabi Bertin Pagna Kagonbe Patrick Mountapmbeme Kouotou Department of Civil Engineering National Advanced School of Engineering University of Maroua Maroua Cameroon Department of Mining Engineering School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon Local Materials Authority Promotion (MIPROMALO) Yaoundé Cameroon Department of Environmental Sciences Advanced School of Agriculture Forestry Water and Environment University of Ebolowa Ebolowa Cameroon

Herein, we report some characteristics of the clayey materials (CMs) collected from Kaliwa (C1), Kabé (C2) and Malo (C3) district in N’Djamena (Chad). Three samples were characterized applying XRF, XRD, FTIR, SEM. In addition, TGA/DSC were performed to control decomposition/mass loss and show phase transitions respectively of CMs. Geochemical analysis by XRF reveals the following minerals composition: SiO2 (~57% - 66%), Al2O3 (~13% - 15%), Fe2O3 (~6% - 10%), TiO2 (~1% - 2%) were the predominant oxides with a reduced proportion in C1, and (~7%) of fluxing agents (K2O, CaO, Na2O). Negligible and trace of MgO (~1%) and P2O5 was noted. The mineralogical composition by XRD shows that, C1, C2 and C3 display close mineralogy with: Quartz (~50%), feldspar (~20%) as non-clay minerals, whereas clays minerals were mostly kaolinite (~15%), illite (~5%) and smectite (~10%). FTIR analysis exhibits almost seemingly similar absorption bands characteristic of hydroxyls elongation, OH valence vibration of Kaolinite and stretching vibration of some Metal-Oxygen bond. SEM micrographs of the samples exhibit microstructureformed by inter-aggregates particles with porous cavities. TGA/DSCconfirm the existence of quartz (570˚C to 870˚C), carbonates (600˚C - 760˚C), kaolinite (569˚C - 988˚C), illite (566˚C - 966˚C), MgO (410˚C - 720˚C) and smectite (650˚C - 900˚C). The overall characterization indicates that, these clayey soils exhibit good properties for ceramic application.

关键词： Clay Soils Characterization Mineralogy Physicochemical Properties Ceramic Application

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