• Composites Research
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• v.35 no.6
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• pp.456-462
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• 2022

Since natural fibers are highly flammable, it is not easy to make them flame retardant. In this study, a liquid flame retardant based on phytic acid, APTES, and Thiourea, which are flame retardant candidates derived from nature, was prepared and its performance was verified through flame retardant treatment and flame retardancy evaluation of bamboo fibers. When a liquid flame retardant is used, it is possible to treat a large amount of natural fibers with flame retardant treatment. Nine types of flame-retardant treated bamboo fibers were prepared according to the Taguchi design of experiment method. Thereafter, vertical burning test and microcalorimeter test were performed for flame retardancy evaluation, and the surface of natural fibers before and after flame-retardant treatment was compared using scanning electron microscope. The results show that phytic acid has a significant effect on improving the flame retardancy of natural fibers. Through microstructure analysis, it was assumed that the phytic acid helps flame retardant to uniformly adhere to the surface of natural fibers. If such research results are utilized, it is possible to make a large amount of natural fibers high flammability in an eco-friendly way, which is expected to be advantageous for the application of prototypes.

• Journal of Life Science
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• v.34 no.8
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• pp.540-547
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• 2024

The continuous use of polymer materials has exacerbated waste and environmental challenges, spurring a growing interest in eco-friendly polymers, especially biodegradable polymers. These polymers are gaining attention for their potential as antimicrobial agents, particularly in fields like food packaging a need further underscored by the recent COVID-19 pandemic. This study focuses on the development of an antibacterial polymer by combining poly-butylene adipate terephthalate (PBAT) with zinc pyrithione (ZnPt). The antibacterial properties were assessed through turbidity analysis, the shaking flask method, and the film adhesion method. The antibacterial activities of the composites with varying ZnPt% (w/w) contents (0, 0.1, 0.3, and 0.5) were evaluated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Results revealed that even at a low concentration of 0.1% (w/w), the composites demonstrated significant antibacterial activity against both Gram-positive bacteria (S. aureus) and Gram-negative bacteria (E. coli). Composites with ZnPt concentrations of 0.3% (w/w) or higher achieved over 99.999% antibacterial efficacy. Field emission scanning electron microscopy (FE-SEM) analysis of the fracture surfaces of the composites confirmed the uniform distribution of ZnPt particles, ranging from 1-4 ㎛. Further FE-SEM analysis of bacterial suspensions exposed to the composite surfaces showed clear evidence of cell wall destruction in both E. coli and S. aureus. As an antimicrobial biodegradable polymer, PBAT-ZnPt composites show great promise for applications in various sectors, including food packaging.

• Journal of Environmental Science International
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• v.21 no.4
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• pp.507-515
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• 2012

To improve the mechanical properties of hydroxyapatite (HA)/waterborne polyurethane (WBPU) composites, the hydroxyl group of HA was modified by urethane reactions: the hydroxyl groups of HA were reacted with aliphatic or cyclic diisocyanate, and then the modified HAs were extended by adding polyol and/or ${\varepsilon}$-caprolactone. Composites were prepared by the prepolymer process method: the modified HA was directly pured into the urethane reaction of isocyanate and polyol. The properties of modified HA/WBPU composites were investigated by thermogravimetric analysis, tensile strength, and water resistance. The results showed that the reactivity of aliphatic diisocyanate to the hydroxy group of HA was faster than that of cyclic one. Comparing to those of pure HA/WBPU composite films, the thermal stability, water resistance, and mechanical properties of the modified composite films increased with a degree of modification of HA.

• Particle and aerosol research
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• v.13 no.4
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• pp.183-189
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• 2017

Potassium hexatitanate ($K_2Ti_6O_{13}$) with high thermal insulating capacity, good mechanical properties, and excellent chemical stability are promising functional materials in the field of reinforcing material, heat insulating paints and automotive brake linings. In this study, we successfully synthesized rod-shaped potassium hexatitanate ($K_2Ti_6O_{13}$) by aerosol spray drying and post heat treatment as an eco-friendly process. The $KHCO_3-TiO_2$ porous particles were firstly synthesized from a colloidal mixture of $K_2CO_3$ and $TiO_2$ via aerosol spray drying. Size of $KHCO_3-TiO_2$ porous particles was ranged from $1{\mu}m$ to $5{\mu}m$. The porous particles were then heated to fabricate rod-type $K_2Ti_6O_{13}$. The length and width of rod-type composites were affected by temperature and heating time. The length and width of $K_2Ti_6O_{13}$ were increased by 830 nm and 500 nm, respectively, as the reaction temperature and time increased.

• Journal of Mushroom
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• v.21 no.3
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• pp.83-87
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• 2023

The importance of biocomposites has increased owing to the changes in global consumption trends and rapid climate change. Technologies using mushroom mycelium cultivation, and molding methods for mycelial application have gained attention as potential strategies for producing eco-friendly composites. Currently, mushroom mycelia are used as raw materials for food and cosmetics; however, research on their utilization as biocomposite materials is limited. Therefore, the potential for the development of mushroom mycelium-related products and technologies is high. This review analyzes the domestic and international patent application trends related to the technologies for composite (packaging, insulation, adhesives, and leather) and food (substitute for meat) materials using mushroom mycelium, as an eco-friendly biocomposite material, to provide objective patent information that can further research and development (R&D) in this field.

• Composites Research
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• v.27 no.1
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• pp.19-24
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• 2014

In this study, an investigation on mechanical properties of flax/vinyl ester natural fiber composite was performed as a precedent study on the design of eco-friendly structure using flax/vinyl ester composite. Vacuum Assisted Resin Transfer Molding(VARTM) manufacturing method was adopted for manufacturing the flax fiber composite specimen. The mechanical properties of the manufactured flax composites were compared with flax composite data cited from some references. Based on this, the experimental data showed that the flax/vinyl ester composite has some advantages when it is applied to environment-friendly structure.

• Elastomers and Composites
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• v.46 no.1
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• pp.22-28
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• 2011

Various materials are used as electrical barrier materials, such as glass, insulating oil, gas, paper and polymer. These materials shut off electricity from conductor as a barrier and separate as well as support conductor from outside environment while using electrical equipment. Polymers are generally used for cable insulation material. Recently environmental regulation are reinforced and eco-friendly materials are in trend.

• Structural Engineering and Mechanics
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• v.70 no.2
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• pp.233-243
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• 2019

This paper depicts the development and characterizations of laminated composites made with cellulosic giant cane (Arundinaria gigantea) fiber mats and epoxy resin. Zirconia-toughened mullite (ZTM) is used as a filler material in the laminated composite which was prepared from sillimanite through plasma processing technique. The mechanical characterizations of this composite have been carried out as per ASTM standards to evaluate its usability as a structural material. The effects of varying weight percentages of the filler and two different fiber orientations namely, angle-ply [$+45^{\circ}/-45^{\circ}/+45^{\circ}$] and balanced cross-ply [$0^{\circ}/90^{\circ}/0^{\circ}$] on the physical and mechanical properties such as density, microhardness, impact strength, tensile strength and interlaminar shear strength of the layered composite specimens have been investigated. The study indicates that the inclusion of zirconia-toughened mullite in the composite laminate as filler improves its mechanical properties. Moreover, the use of giant cane fiber mat in the laminate is more eco-friendly than the synthetic fibers. This research also helps in generating additional data to enrich the repository of natural fiber reinforced laminated composites.

• Composites Research
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• v.36 no.4
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• pp.264-269
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• 2023

Spent coffee grounds (SCG) are a ubiquitous byproduct of coffee consumption, representing a significant waste management challenge, as well as an untapped resource for economic development and sustainability. Improper disposal of SCG can result in environmental problems such as methane emissions and leachate production. This study aims to investigate the physicochemical properties of SCG and their potential as a reinforcement material in polypropylene (PP) to fabricate an eco-friendly composite via extrusion and injection molding, with SCG filler ratios ranging from 5-20%. To evaluate the effect of SCG on the morphological and mechanical properties of the bio- composite, thermogravimetric analysis, SEM, tensile, flexural, and impact tests were conducted. The results demonstrated that the addition of SCG lead to a slight increase in brittleness of the composite but did not significantly affect its mechanical properties. Impressively, the presence of a significant organic component in SCG contributed to the enhanced thermal performance of PP/SCG composites. This improvement was evident in terms of increased thermal stability, delayed onset of degradation, and higher maximum degradation temperature as compared to pure PP. These findings suggest that SCG has potential as a filler material for PP composites, with the ability to enhance the material's properties without compromising overall performance.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.98-101
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• 2011

A 10 nm nano-silica was introduced to a conventional 3 ${\mu}M$ micro-silica composite to develop an eco-friendly new electric insulation material for heavy electric equipment. Thermal and mechanical properties, such as glass transition temperature (Tg), dynamic mechanical analysis, tensile and flexural strength, were studied. The mechanical results were estimated by comparing scale and shape parameters in Weibull statistical analysis. The thermal and mechanical properties of conventional epoxy/micro-silica composite were improved by the addition of nano-silica. This was due to the increment of the compaction via the even dispersion of the nano-silica among the micro-silica particles.