Papers by Keyword: Natural Polymer

Abstract: A biopolymer electrolyte made from natural polymer consists of jackfruit seed starch (JSS) and polyvinyl alcohol (PVA) with a different composition of zinc oxide (ZnO) was prepared using the solution casting method. The incorporation of metal oxides such as ZnO into natural polymers can improve the electrical properties, which can produce biodegradable energy storage devices. This innovation may aid in the reduction of the use of electronic devices, which generate e-waste. Thus, this study was conducted to investigate the effect of ZnO addition to the biopolymer in terms of its electrical properties. The samples were prepared by using the solution casting method. Different percentages of ZnO were mixed with JSS, PVA, hydrocloric acid, sodium hydroxide, and glycerol before being moulded in a petri dish and dried at room temperature. The electrical properties of the blends were then characterized by using an Agilent 4284a Precision LCR meter. The highest ionic conductivity value for JSS and PVA after the addition of ZnO is 1.10x10-6 Scm-1 with 10% of ZnO, and the lowest conductivity is 2.11x10-7 Scm-1 with 14% of ZnO. The dielectric and electric modulus were further studied in order to understand the electrode polarization effect.

Abstract: Biodeterioration of lignocellulosic materials is a worldwide problem and it causes a great damage especially to unique manuscripts and books stored in libraries. These materials are permanently subject to suffering from physical, chemical, and/or biological changes. Biological deterioration by microorganisms (bacteria and fungi) causes undesirable changes on material properties. Paper made by vegetal fibers, functional additives (glue, optical polishers, consolidating nts), and inks with organic bindings are used as sources of nutrients. Using of EOs (essential oils) for protection against microorganisms appears to be an option, because antimicrobial effects of the main compounds of EOs were proven. This work analyzes the antimicrobial stability of 2 essential oils (citral and linalyl acetate), as well as their stability of mechanical properties, in selected lignocellulosic materials (soft wood and hard wood kraft pulp, softwood sulphite pulp). Some parts of samples were subjected only to the condition of the EOs, other samples were firstly treated by accelerated ageing. Last samples were exposed to the accelerated ageing and afterwards treated by EOs. From the mechanical properties measuring of samples it is possible to state that in some SAJ samples the influence of EOs vapour is positive. This was monitored even when the samples were treated by accelerated ageing.

Abstract: In order to induce bone regeneration several natural and synthetic materials have been proposed. However, single-phase scaffolds present some insurmountable disadvantages such as poor mechanical strength or brittleness and too low or too high degradation rate. In order to overcome these drawbacks, composite systems can be an interesting and promising option. In the present work a novel hybrid porous scaffold for bone tissue engineering is proposed. Chitosan/Forsterite (Ch/FS) composite scaffolds were prepared by freeze-drying method using a chitosan/forsterite ratio of 90/10. The FS nanopowder (Mg₂SiO₄) is synthesized using a simple solgel based method. The FS composition was checked by XRD analysis. The macrostructure of the Ch/FS scaffolds were analyzed by SEM, the FS distribution within the chitosan matrix observed by EDS, the mechanical strength measured by compression test in PBS and the biocompatibility of the composite on human osteosarcoma cell line (MG-63) verified by MTT assay after 48 hours. The porosity appears interconnected and with a pore size ranging from 1 to 100 μm. The FS is overall distributed within the chitosan matrix. The compression strength of composite scaffolds increased with respect to the pure chitosan scaffolds of more than two times (from 0.8 to 1.9 KPa) and the composites did not show any toxicity effect on human osteosarcoma cells.

Abstract: Current trend has demonstrated the implementation of natural polymers as alternative materials in various engineering applications including biomaterials and biomedical applications. This paper reviews the potential of Cellulose Phosphate derived from Oil Palm Empty Fruit Bunch (OPEFB-CP) as a biomedical material. OPEFB-CP will act as reinforcement to glass materials in fabricating good and flexible scaffold composite materials. A 3-dimensional scaffold composite material comprised of the cellulose phosphate and glass material was produced by using a sol-gel technique. The composite biomaterial is expected to have degraded together as one material.

Abstract: In this paper, the Food-grade sea cucumber / gelatin nanofiber was for the first time successfully prepared with electrospinning method. With the help of the infrared spectroscopy and X-ray diffraction, this paper analyzed the content of the nanosea cucumber powder and gelatin as well as the impact of different preparation methods on the crystalline of the Fiber membrane. Furthermore, Scanning electron microscope (SEM) was utilized to observe the fiber morphology, and thus discuss the best content of gelatin. The Experimental result manifested that as electrospinning method was used in preparing the Food-grade sea cucumber / gelatin nanofiber membrane, the nanosea cucumber powder and gelatin dispersed well in the fiber membrane, while it did worse in the crystalline of membrane. As the Gelatin content of the spinning solution is 10 wt. %, the spinnabiliy as well as its fiber-forming properties is of optimum.

Abstract: Unidirectional freeze-drying method has been tried to prepare biomimetic aligned porous materials (APM) from natural macromolecules such as chitosan, gelatin, alginate, carrageenan, various starches, and their composites. All the porous materials have high porosity and surface area, although the pore morphology varies for different sources of natural macromolecules, composition and concentration of solution, as well as crosslinking degree. The APM has potential applications in bioseparation, biomedical engineering, tissue engineering, food and environmental protection.

Abstract: This paper presents a method called zinc oxalate (ZnC₂O₄) recurrence method to prepare porous zinc oxide (ZnO) films via templating with polystyrene (PS) spheres. Effects of calcination time and temperature, concentration of ZnC₂O₄ in precursor solution on ZnO films were studied. Optimal synthetic conditions and structural features of ZnO films were investigated by DTA, XRD and SEM. Experimental results show that porous ZnO films can be easily prepared by zinc oxalate recurrence methods.

Abstract: The development in the area of natural-fibre-reinforced composites has greatly increased in recent years. Using castor oil polyurethane (PU) as matrix for composites reinforced with lignin and cellulose from sugarcane straw is in tune with economical and environmental interests. The aim of this work was the thermal degradation study of castor oil-polyurethane composites reinforced with cellulose from sugarcane straw. For the obtainment of cellulose, sugarcane straw was pretreated by steam explosion, followed by a delignification with NaOH. For the production of the PU, the polyol (castor oil) to diisocyanate mass ratio was 1.5:1.0. Reinforcement of the matrix was done changing the concentration of cellulose fibres (5,10,15,20% w/w). Thermogravimetric analysis of the materials was carried out. The results obtained showed that the process of decomposition of the matrix occurs in one step, while for the composites it occurs in two steps. The addition of reinforcement in the matrix basically did not change the thermal stability of the composite.

Abstract: Natural polymer cationic flocculant was prepared by introducing quaternary ammonium group into the rice husk molecules, using potassium permanganate as initiator. The influence of synthetic conditions affecting flocculation was studied, such as reaction temperature, reaction time, dosage of initiator, concentration of sulfuric acid and material ratio. The flocculent experiment of diatomite was chosen to evaluate the capability of flocculant. The results show that the flocculant has good flocculent capacity, the removal of turbidity can reach above 90% for simulated wastewater under the optimistic conditions of synthetic process as follows: etherification temperature, 50°C; etherification time, 3h; initiator concentration, 3 mmol/L; sulfuric acid concentration, 1.8 mmol/L; ratio of rice husk to OTAC, 2: 3.

Abstract: Silk fibroin (SF) is a protein fiber spun by Bombyx mori silkworm. SF fibers are about 10-25 μm wide in diameter and a single cocoon may provide over 1000 m of SF fibers. SF can present several conformations regarding protein secondary structure which ultimately define the structural properties of SF-based materials. For this reason, a rigorous control on its processing conditions shall be performed. It is known that SF has excellent properties to be used in biomaterials field, controlled release and scaffolds for tissue engineering. In addition, SF can be processed in several forms, such as films, fibers, hydrogels or microparticles. This work seeks to provide an overview on SF processing conditions, regarding the preparation of SF membranes (dense and porous), hydrogels and biocomposites, focusing on biomaterials application.