Vol.8, No.1, 2020-Table of Contents
  • Thermally Reversible, Self-Healing Polyurethane Based on Propyl Gallate and Polyurethane Prepolymers with Varied Isocyanate Content
  • Abstract Thermosetting polyurethanes are widely used in various fields owing to their excellent elasticity, strength and solvent resistance. Three environmental friendly propyl gallate-based self-healing polyurethanes were prepared from polyurethane prepolymers with varying isocyanate content. The thermal stabilities of the polyurethanes were tested using thermogravimetric analysis. Their self-healing and mechanical properties were analyzed using a universal testing machine and dynamic thermomechanical analysis. The polyurethanes were found with high self-healing ability and excellent mechanical properties due to the absence of phenolic carbamate. These qualities improved with increased isocyanate content and the prolonged selfhealing time. We found, therefore, that the propyl gallate-based polyurethane has… More
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  • Mechanical Properties and Stress Strain Relationship Models for Bamboo Scrimber
  • Abstract In order to investigate the basic mechanical properties and stress strain relationship model for bamboo scrimber manufactured based on a new technique, a large quantities of experiments have been carried out. Based on the analysis of the test results, the following conclusions can be drawn. Two main typical failure modes were classified for bamboo scrimber specimens both under tension parallel to grain and tension perpendicular to grain. Brittle failure happened for all tensile tests. The slope values for the elastic stages have bigger discreteness compared with those for the specimens under tensile parallel to grain. The failure modes for bamboo… More
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  • Adsorption Behavior of Reducing End-Modified Cellulose Nanocrystals: A Kinetic Study Using Quartz Crystal Microbalance
  • Abstract In this work, we studied the adsorption of modified cellulose nanocrystals onto solid surfaces by quartz crystal microbalance with dissipation monitoring (QCM-D). Cellulose nanocrystals obtained from tunicate (CNC) were modified at reducing end by amidation reactions. Two different functionalities were investigated: a polyamine dendrimer (CNC-NH2), which interacts with gold surface by the amine groups; and a biotin moiety (CNC-Biot), which has a strong affinity for the protein streptavidin (SAV). QCM-D results revealed different adsorption behaviors between modified and unmodified CNCs. Hence, unmodified CNCs covered almost all the surface forming a rigid and flat layer whereas reducing end modified CNCs remained… More
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  • The Effects of DOPO-g-ITA Modified Microcrystalline Cellulose on the Properites of Composite Phenolic Foams
  • Abstract In order to improve the comprehensive performance of phenolic foam, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) was grafted with itaconic acid (ITA) (DOPO-g-ITA) to modify microcrystalline cellulose (MCC). DOPO-g-ITA modified MCC (DIMMCC) was used to prepare composite phenolic foam (DCPF). The structures of DIMMCC were verified by Fourier transform infrared spectroscopy (FT-IR). The microstructure and crystalline property were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. Compared with MCC, the crystallinity of DIMMCC was dramatically decreased, but the diffraction peak positions were unchanged. Thermal stability was decreased, and Ti decreased by 45.0°C. The residual carbon (600°C) was increased by 22.34%.… More
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  • Synthesis and Characterization of UV Oligomer based on Cardanol
  • Abstract In the present research, cardanol based di-acrylic UV oligomer was synthesized by thiol-ene coupling followed by ring opening reaction with glycidyl methacrylate. The intermediate as well as final diacrylate materials were analyzed by chemical as well as spectroscopic analysis. Further, ultraviolet (UV) radiation curable formulations were prepared by replacing commercial epoxy acrylate with synthesized UV oligomer in 10-50 wt% and applied on wood panels. The coated films were then evaluated for their optical, mechanical, chemical and thermal properties. Studies showed that up to 30 wt% amount of UV oligomer the coatings exhibited at par mechanical and chemical properties. The stain… More
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  • Green Synthesis of Silver Nanoparticles from Abronia villosa as an Alternative to Control of Pathogenic Microorganisms
  • Abstract The aim of this study was to evaluate the antibacterial and antifungal activities of eco-friendly synthesized silver nanoparticles. The silver nanoparticles were synthesized by biological method using aqueous extract of Abronia villosa. Synthesis of silver nanoparticles was confirmed by color change and characterized using UV-visible spectroscopy, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), and zeta potential analysis. The SEM analysis revealed the presence of spherical silver nanoparticles of the size range 21 to 33 nm. Synthesized silver nanoparticles were used to evaluate their antibacterial effects at different concentrations (25, 50, 75 and 100 µg/ml)… More
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  • Mannonic Acid and Bio-Ethanol Production from Konjac Using a Two-Step Bioprocess with Candida Shehatae and Gluconobacter Oxydans
  • Abstract Amorphophallus konjac is rich in glucomannan, which can be hydrolyzed into glucose and mannose, thereby acting as an economic raw material for the acquisition of glucose and mannose. The total sugar yield was 91.2% when konjac powder was treated with 0.75% hydrochloric acid at 121°C for 1 h. Thus, dilute acid hydrolysates of konjac powder were used as a carbon source for obtaining value-added products. Here we showed that the microbial production of ethanol and mannonic acid was obtained by employing Candida shehatae (C. shehatae) and Gluconobacter oxydans (G. oxydans). Through a step-by-step bioprocess, glucose is the first selectively converted… More
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  • Poly (vinyl alcohol)/Graphene Nanocomposite Hydrogel Scaffolds for Control of Cell Adhesion
  • Abstract Poly (vinyl alcohol) (PVA)/reduced graphene oxide (rGO) nanocomposites is prepared by the immersion of PVA/graphene oxide (GO) nanocomposites in the reducing agent aqueous solution. The PVA/graphene nanocomposites can be used as scaffold after treatment by chemical crosslinking agents. The surface hydrophilicity of the nanocomposite scaffolds decreased with the addition of GO or rGO by measuring the contact angles of scaffolds. The electrical conductivity of PVA/rGO nanocomposite scaffold increased with rGO content increased. The highest conductivity of PVA/rGO nanocomposite scaffolds with 10 wt% rGO could reach to 12.16 × 10−3 S/m. The NIH-3T3 fibroblasts attach and grow well on the surface… More
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  • Two Routes to Produce Chitosan from Agaricus bisporus
  • Abstract Two methods were used to produce chitosan by deacetylation of chitin which was extracted from Agaricus bisporus stipes. The first one gives chitosan 1 with low yield of 2.5%, degree of acetylation (DA) of 4%, molecular weight (MW) of 2.973 × 105 (g/mol). The second route produces chitosan 2 with higher yield of 41%, degree of acetylation (DA) of 17.23%, molecular weight (MW) of 2.939 × 105 (g/mol). Both chitosans were characterized by XRD, FTIR, 1 H-NMR spectroscopy nuclear magnetic resonance of proton. The molecular weight (MW) was determined by size exclusion chromatography (SEC). Thermal analysis shows that both chitosans… More
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