To improve the flame retardant performance of cellulose fibers, fluorine functional groups were introduced under various controlled fluorination conditions. The properties of the fluorinated cellulose fibers were analyzed by X-ray photoelectron spectroscopy and a thermogravimetric analysis. The fluorine functional group content in the fluorinated cellulose fibers increased with an increase in the fluorination temperature. However, the fluorination reaction increased the char yield and decreased the rate of degradation of the cellulose fibers by introducing donors, enabling the formation of a thick and compact char layer. Therefore, the flame retardant properties of cellulose fibers were improved following the fluorination treatment.

Conductive and dielectric SiC are fabricated using electroless plating of Ni–Fe films on SiC chopped fibers to obtain lightweight and high-strength microwave absorbers. The electroless plating of Ni–Fe films is achieved using a two-step process of surface sensitizing and metal plating. The complex permeability and permittivity are measured for the composite specimens with the metalized SiC chopped fibers dispersed in a silicone rubber matrix. The original noncoated SiC fibers exhibit considerable dielectric losses. The complex permeability spectrum does not change significantly with the Ni–Fe coating. Moreover, dielectric constant is sensitively increased with Ni–Fe coating, owing to the increase of the space charge polarization. The improvements in absorption capability (lower reflection loss and small matching thickness) are evident with Ni–Fe coating on SiC fibers. For the composite SiC fibers coated with Ni–Fe thin films, a -35 dB reflection loss is predicted at 7.6 GHz with a matching thickness of 4 mm.

본 연구에서는 활성탄소섬유를 이용하여 축전식 탈염공정에 적용할 탄소전극을 제조하였다. polyvinylidene fluoride (PVDF)를 바인더로 사용했으며 적절한 용매에 활성탄소섬유를 배합한 후 상용의 그라파이트 시트에 캐스팅하여 탄소전극을 제조하였다. 이 때 활성탄소섬유의 입자 크기를 달리하였고, 용매, 고분자 바인더 그리고 활성탄소섬유를 80 : 2 : 18, 80 : 5 : 15의 배합비율로 전극을 제조하였다. 그런 다음 염 제거 효율을 흡착전압과 시간, 탈착전압과 시간, NaCl 공급액의 농도와 유속 등에 운전조건에 대하여 염 제거 효율을 측정하였다. 대표적으로 활성탄소섬유의 입자크기가 32 μm 이하이며 80 : 2 : 18의 배합비율에서 1.2 V, 3분의 흡착조건, -0.1 V, 1분의 탈착조건, NaCl 100 mg/L, 15 mL/min의 공급액 조건에서 53.6%의 염 제거 효율을 보였다.

TiO2-doped activated carbon fibers (ACFs) were successfully prepared as capacitive deionization (CDI) electrode materials by facile ultrasonication-assisted process. ACFs were treated with titanium isopropoxide (TTIP) and isopropyl alcohol solutions of different concentrations and then calcinated by ultrasonication without heat-treatment. The results show that a certain amount of anatase TiO2 was present on the ACF surface. The specific capacitance of the TiO2-doped ACF electrode was remarkably improved (by 93.8% at scan rate of 50 mV s–1) over that of the untreated ACF electrode, despite decreases in the specific surface area and total pore volume upon TiO2 doping. From the CDI experiments, the salt adsorption capacity and charge efficiency of the sample with TTIP percent concentration of 15% were found to considerably increase by 71.9 and 57.1%, respectively. These increases are attributed to the improved wettability of the electrode, which increases the number of surface active sites and facilitates salt ion diffusion in the ACF pores. Additionally, the Ti-OH groups of TiO2 act as electrosorption sites, which increases the electrosorption capacity.

Fly ash is used as alumina-silicate resource material to reaction processing on geopolymer materials. The strength of material is belonging to alkaline liquid, fly ash, activity reaction of fly ash. Geopolymer concrete as non-toxic, bleed free and high strength material can be used for construction on rigid pavement. Study on influence of polypropylene fiber on performance characteristic of geopolymer concrete is considered. In this research, the mix proportion with fly ash and alkaline liquid is used to react on geopolymer concrete. The poly-propylene fiber in range from 0 to 0.5% by volume is added in mixture of geopolymer concrete. The ratio between length and diameter in range of 100-500 is investigated. The results are indicated that workability of fresh concrete is reduced by using poly-propylene fiber. The adding of poly-propylene fiber is significantly affected on characteristic of geopolymer concrete. Poly-propylene fiber can be distributed in fly ash matrix and reduced shrinkage of concrete during activation. After geopolymerization, compressive and the flexural strength of concrete produced with fibers are enhanced up to 10% and 20%, respectively. However, when the length to diameter ratio increases, compressive strength is tended to decrease with mixture using polypropylene fiber.

This study evaluated the effect of steel slag and steel wool fibers (SWF) on self-healing performance of asphalt mixture. The microstructure and distribution of SWF in mixture were examined by a computerized tomography scan and image analysis program. Thermal conductivity was investigated using the thermal constant analyser. The heating rate and healing performance were measured by induction heating system. The results showed the uneven distribution and the agglomeration in the mixtures when the content of fibers exceed a certain dosage. It was found that the mix with steel slag had higher heating rate than the mix with normal aggregate; however, its healing performance was slightly lower because of the breaking of weak steel slag. Finally, the mechanical test results indicated that SWF can enhance the resistance and prolong the fatigue life of asphalt mixtures.

In pressure retarded osmosis (PRO) process, thin film composite (TFC) type membranes which can withstand high operating pressure are required. In this study, glass fibers (GF) are used as additive for mechanical strength enhancement of the support layer of TFC membranes. The support layers were fabricated by a phase inversion method by using the casting solution of blended GF (two different size of milled GF) with polyethersulfone (PES). The fabricated support layers were characterized by FE-SEM, FT-IR, contact angle goniometer, and universal testing machine. Lab-scale ultrafiltration experiment was carried out to measure their performance. As a result, the support layer with milled GF showed higher mechanical strength and water flux than the pure PES support layer, and the support layer with smaller size GF showed higher performance.

PURPOSES: This study develops eco-friendly asphalt reinforcement materials applicable to bridge deck pavement. The main purpose is to ensure highly reliable quality applicable to structures and the possibility of practical application. The main target of the study is to develop materials that are environmentally friendly and capable of improving performanceMETHODS: The application of double-reinforcement fiber improves the performance of the road pavement. 1. We use recycled film for application of sheet-typed reinforcement. 2. We use preprocessing fibers to reinforce the properties of composite pavement materials.RESULTS : The developed products may produce materials that fit the purpose of achieving stability and environmental friendliness. Sheettyped reinforcements use more than 50% recycled resin. The most important type of damage to the asphalt layer is deflection (plastic deformation). These products have a very high deflection resistance of not less than 6,000 cycles/mm. In addition, all performance is excellent. Thus, it will be easier to access the field in the future.CONCLUSIONS: Fiber-reinforced asphalt pavement showed excellent performance. Sheet-typed reinforcements containing 50% recycling resin produced good performance in terms of functionality as well as environmental friendliness. Thus, enhancing the field applicability will enhance the usability of the reinforcements.

Graphite fibers are materials with a high specific modulus that have attracted much interest in the aerospace industry, but their high manufacturing cost and low yield are still problems that prevent their wide applications in practice. This paper presents a laser-based process for graphitization of carbon fiber (CF) and explores the effect of laser radiation on the microstructure of CF. The obtained Raman spectra indicate that the outer surface of CF evolves from turbostratic structures into a three-dimensional ordered state after being irradiated by a laser. The X-ray diffraction data revealed that the growth of crystallite was parallel to the fiber axis, and the interlayer spacing d002 decreased from 0.353 to 0.345 nm. The results of scanning electron microscopy revealed that the surface of irradiated CFs was rougher than that of the unirradiated ones and there were scale-like small fragments that had peeled off from the fibers. The tensile modulus increased by 17.51% and the Weibull average tensile strength decreased by 30.53% after being irradiated by a laser. These results demonstrate that the laser irradiation was able to increase the graphitization degree of the CFs, which showed some properties comparable to graphite fibers.

We demonstrated an effective way of preparing melt spinnable mesophase pitches via catalytic hydrogenation of petroleum residue (fluidized catalytic cracking-decant oil) and their subsequent thermal soaking. The mesophase pitches thus obtained were analyzed in terms of their viscosity, elemental composition, solubility, molecular weight, softening point and optical texture. We found that zeolite-induced catalytic hydrogenation under high hydrogen pressure contributed to a large variation in the properties of the pitches. As the hydrogen pressure increased, the C/H ratio decreased, and the solubility in n-hexane increased. The mesophase pitch with entirely anisotropic domains of flow texture exhibited good meltspinnability. The mesophase carbon fibers obtained from the catalytically hydrogenated petroleum residue showed moderate mechanical properties.

This study measured dyeing properties under different dyeing conditions and levels of antimicrobial activity when man-made fibers are dyed with gallnut, including rayon, tencel, tencel blended fabric, soybean fiber, and nylon non-mordanted. The dye up-take (K/S), color (L*a*b*), and color differences (△E) were measured with a colorimeter, and the number of bacteria present in the dyed fabrics were determined using Staphylococcus aureus and Klebsiella pneumonia as strains. The results are as follows: First, the optimal dyeing conditions for man-made fibers dyed with gallnut are 60 minutes of dyeing time and a 80℃ dyeing temperature. Second, gallnut dye is most effective on soybean fiber and then, in descending order of effectiveness, on nylon, rayon, tencel, and tencel blended fabric. This means that dyeing properties of nitrogen containing fibers are excellent when using gallnut. Third, all man-made fibers are dyed brown with gallnut. This implies dyeing possibility of man-made fibers about gallnut dye, so development and supply of natural dyed goods of man-made fibers can be increased. Fourth, in all man-made fibers dyed with gallnut extract, both Staphylococcus aureus and Klebsiella pneumonia show 99.9% reduction ratios of fungistasis, which indicate antimicrobial activity. Therefore, safe, functional, man-made materials can be developed to relieve symptoms from and treat patients with skin ailments.

In order to improve the high temperature oxidation resistance and lifespan of mat type porous carbon insulation, SiC was coated on carbon insulation by solution coating using polycarbosilane solution, curing in an oxidizing atmosphere at 200 oC, and pyrolysis at temperatures up to 1200 oC. The SiOC phase formed during the pyrolysis process was converted into SiC crystals as the heat treatment temperature increased, and a SiC coating with a thickness of 10-15 nm was formed at 1600 oC. The SiC coated specimen showed a weight reduction of 8.6 % when it was kept in an atmospheric environment of 700 oC for 1 hour. On the other hand, the thermal conductivity was 0.17W/mK, and no difference between states before and after coating was observed at all.

목 적 : MRI는 부분 영역을 자세히 영상화하는 검사이다. 그럼에도 불구하고 인체에 위해 한 RF를 전신에 주고 있다. 따라 서 본 연구에서는, 부분 촬영 시 RF를 차단할 수 있는 방호복을 자체 제작하여 적용함으로써, 전신에 인가되는 RF로 인해 발생할 수 있는, 온도 상승으로 인한 인체의 위해를 방지하고자 하였다. 대상 및 방법 : 연구 방법은, RF 차단 섬유의 성능을 평가하기 위해, 원통형 fluid phantom을 이용하여 phantom 실험을 시 행한 후 그 결과를 바탕으로 방호복을 제작하여 무릎에 임상실험을 시행하였다. 영상 획득은, 3.0T 초전도 자기공명영상장 치와 32 channel anterior 코일을 사용하여, T1 WI, T2 WI, T2 FS 영상을 획득하였고, 영상 측정 프로그램을 이용하여 영상의 소거 정도와 aliasing artifact 발생 정도를 측정하였으며, 대응 표본 T 검정을 이용하여 적용 전, 후에 따른 유의한 차이가 있는지 비교 평가하였다. 결 과 : 실험 결과, phantom 실험의 경우, 영상의 소거 정도와 aliasing artifact 발생 정도 모두 적용 전보다 후가 평균 98.94% 감소하였다. 이는, RF 차단 섬유가 RF를 완벽히 차단한다는 것으로, RF가 인체와 반응하지 못했다는 것을 의미한 다. 이와 같은 결과는 임상실험 결과를 통해서도 알 수 있는데, 임상실험 또한, phantom 실험과 마찬가지로 영상의 소거 정도와 aliasing artifact 발생 정도 모두 적용 전보다 후가 평균 95.89% 감소하였다. 결과를 종합해 보면, 본 연구의 방호복이 RF를 완벽히 차단하여 인체에 유해한 온도 상승을 제어할 수 있는 가장 직접적인 개선 방안이다. 결 론 : 본 연구에서 제시한 RF 방호복은, RF와 인체와의 상호작용을 원천적으로 차단할 수 있어 규정된 SAR의 초과 우려가 없으며, 이는 곧 온도 상승으로 인해 인체에 발생할 수 있는 위해를 감소시킬 수 있다. 따라서 저자들은 주자장이 높아지고 있는 현 상황에서 본 연구가 제시한 RF 방호복이, 부분 촬영 시 전신에 인가되는 RF로 인해 발생할 수 있는 인체의 위해를 줄일 수 있는 최적의 대안이라고 생각한다.