Vol.8, No.4, 2020-Table of Contents
  • Physicochemical Characterization and Antimicrobial Properties of Inulin Acetate Obtained by Microwave-Assisted Synthesis
  • Abstract Microwave-assisted irradiation was performed for esterification of chicory inulin with high degree of polymerization with acetic anhydride without a solvent only with a catalyst. The resulting esters were characterized by melting point, hydrophilic-lipophilic balance, thin-layer chromatography, ultraviolet spectroscopy, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. Inulin acetate demonstrated a high degree of acetylation (2.5–3.0) and presented a white, water-insoluble substance with bitter taste. The FTIR and NMR spectra confirmed esterification and demonstrated the incorporation of hydrophobic residue to the water soluble inulin backbone. Swelling capacity, water holding, oil-holding capacities, the foamability, foam stability and emulsifying properties… More
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  • Composite Biomaterials Based on Poly(L-Lactic Acid) and Functionalized Cellulose Nanocrystals
  • Abstract The biocomposite films were prepared from poly(L-lactic acid) and cellulose nanocrystals. To improve interfacial compatibility of hydrophilic cellulose nanocrystals with hydrophobic matrix polymer as well as to provide the osteoconductive properties, cellulose was functionalized with poly(glutamic acid). The modified cellulose nanocrystals were better distributed and less aggregated within the matrix, which was testified by scanning electron, optical and polarized light microscopy. According to mechanical tests, composites filled with nanocrystals modified with PGlu demonstrated higher values of Young’s modulus, elongation at break and tensile strength. Incubation of composite materials in model buffer solutions for 30 weeks followed with staining of Ca2+ More
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  • Synthesis and Properties of Thermoplastic Polyisocyanurates: Polyisocyanuratoamide, Polyisocyanurato(Ester-Amide) and Polyisocyanurato (Urea-Ester)
  • Abstract It has been proved that introducing isocyanurate into polymer chains could improve the flame retardancy of polymers. We describe in this work the synthesis and the thermal property study of three thermoplastic polyisocyanurates, which are polyisocyanuratoamide (PICA-6), polyisocyanurato(ester amide) (PICEA-6) and polyisocyanurato(urea ester) (PICUE-6). These polymers show similar and improved thermal stability with the existence of isocyanurate rings. PICA-6 is more crystalizable than the rest two and the melting temperature is found to be around 240°C but it still crystalizes slowly. For PICEA-6 and PICUE-6, only glass transition can be observed on the DSC traces. The glass transition temperature follows… More
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  • Synthesis and Interfacial Properties of Bio-Based Zwitterionic Surfactants Derived from Different Fatty Acids in Non-Edible Vegetable Oils
  • Abstract Waste cooking oils and non-edible vegetable oils are abundant and renewable resources for bio-based materials which have showed great potential applications in many industries. In this study, five fatty acids commonly found in non-edible vegetable oils, including palmitic acid, stearic acid, linoleic acid, linolenic acid, ricinoleic acid, and their mixtures, were used to produce bio-based zwitterionic surfactants through a facile and high-yield chemical modification. These surfactants demonstrated excellent surface/interfacial properties with the minimum surface tensions ranging from 28.4 mN/m to 32.8 mN/m in aqueous solutions. The interfacial tensions between crude oil and surfactant solutions were remarkably reduced to lower values… More
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  • Sunflower-Like SrCo2S4@f-MWCNTs Hybrid Wrapped by Engineering N-Reduced Graphene Oxide for High Performance Dye-Sensitized Solar Cells
  • Abstract A novel sunflower-like nanocomposite of SrCo2S4 nanoflakes and functionalized multiwall carbon nanotubes (f-MWCNTs) entanglement enveloped in nitrogen-reduced graphene oxide (N-RGO) is prepared by a cheap process. The unique entanglement structure of the material exhibits higher specific surface area, better electrical conductivity and other properties. This helps to reduce the transfer resistance in the photoelectric process of the battery and improve the electrochemical activity, thus increasing the photoelectric conversion efficiency of the battery. The new ternary cobalt-based sulfide material can replace platinum as the counter electrode (CE) material loaded on dye-sensitized solar cells (DSSCs). DSSCs with SrCo2S4@f-MWCNTs@N-RGO (SCS@f-M@N-R) as CE material… More
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  • Preparation of Dicarboxyl Cellulose Nanocrystals from Agricultural Wastes by Sequential Periodate-Chlorite Oxidation
  • Abstract Agricultural waste straw is the renewable resource with the highest annual yield in the world. In value-added applications of agricultural waste, dicarboxyl cellulose nanocrystals (DCCs) are prepared from rice, wheat, and corn straw by sequential periodate-chlorite oxidation. In this study, DCCs from rice, wheat, and corn straw were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometer, X-ray diffractometer (XRD), and thermal gravimetric analysis (TGA). The carboxyl content of the DCCs was also investigated. XRD results show that the crystallinity index decreased after sequential periodate-chlorite oxidation; however, the cellulose I structure was maintained. TEM results show that rod-shaped DCCs… More
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