In this work, the effects of maleic anhydride (MA) content on mechanical properties of chopped carbon fibers (CFs)-reinforced MA-grafted-polypropylene (MAPP) matrix composites. A direct oxyfluorination on CF surfaces was applied to increase the interfacial strength between the CFs and MAPP matrix. The mechanical properties of the CFs/MAPP composites are likely to be different in terms of MA content. Surface characteristics were observed by scanning electron microscope, Fourier transform infrared spectroscopy, and single fiber contact angle method. The mechanical properties of the composites were also measured by a critical stress intensity factor (KIC). From the KIC test results, the KIC values were increased to a maximum value of 3.4 MPa with the 0.1 % of MA in the PP, and then decreased with higher MA content.

Much attention has been paid to thermally conductive materials for efficient heat dissipation of electronic devices to maintain their functionality and to support lifetime span. Hexagonal boron nitride (h-BN), which has a high thermal conductivity, is one of the most suitable materials for thermally conductive composites. In this study, we synthesize h-BN nanocrystals by pyrolysis of cost-effective precursors, boric acid, and melamine. Through pyrolysis at 900oC and subsequent annealing at 1500oC, h-BN nanoparticles with diameters of ~80 nm are synthesized. We demonstrate that the addition of small amounts of Eu-containing salts during the preparation of melamine borate precursors significantly enhanced the crystallinity of h-BN. In particular, addition of Eu assists the growth of h-BN nanoplatelets with diameters up to ~200 nm. Polymer composites containing both spherical Al2O3 (70 vol%) and Eu-doped h-BN nanoparticles (4 vol%) show an enhanced thermal conductivity (λ ~ 1.72W/mK), which is larger than the thermal conductivity of polymer composites containing spherical Al2O3 (70 vol%) as the sole fillers (λ ~ 1.48W/mK).

Ni nanoparticles (NPs)-graphitic carbon nanofiber (GCNF) composites were fabricated using an electrospinning method. The amounts of Ni precursor used as catalyst for the catalytic graphitization were controlled at 0, 2, 5, and 8 wt% to improve the photovoltaic performances of the nanoparticles and make them suitable for use as counter electrodes for dyesensitized solar cells (DSSCs). As a result, Ni NPs-GCNF composites that were fabricated with 8 wt% Ni precursors showed a high circuit voltage (0.73 V), high photocurrent density (14.26 mA/cm2), and superb power-conversion efficiency (6.72 %) when compared to those characteristics of other samples. These performance improvements can be attributed to the reduced charge transport resistance that results from the synergetic effect of the superior catalytic activity of Ni NPs and the efficient charge transfer due to the formation of GCNF with high electrical conductivity. Thus, Ni NPs-GCNF composites may be used as promising counter electrodes in DSSCs.

Ni nanoparticles (NPs)-graphitic carbon nanofiber (GCNF) composites were fabricated using an electrospinning method. The amounts of Ni precursor used as catalyst for the catalytic graphitization were controlled at 0, 2, 5, and 8 wt% to improve the photovoltaic performances of the nanoparticles and make them suitable for use as counter electrodes for dyesensitized solar cells (DSSCs). As a result, Ni NPs-GCNF composites that were fabricated with 8 wt% Ni precursors showed a high circuit voltage (0.73 V), high photocurrent density (14.26 mA/cm2), and superb power-conversion efficiency (6.72 %) when compared to those characteristics of other samples. These performance improvements can be attributed to the reduced charge transport resistance that results from the synergetic effect of the superior catalytic activity of Ni NPs and the efficient charge transfer due to the formation of GCNF with high electrical conductivity. Thus, Ni NPs-GCNF composites may be used as promising counter electrodes in DSSCs.

Particle morphology change and different experimental condition analysis during composite fabrication process by traditional ball milling with discrete element method (DEM) simulation were investigated. A simulation of the three dimensional motion of balls in a traditional ball mill for research on the grinding mechanism was carried out by DEM simulation. We studied the motion of the balls, the ball behavior energy and velocity; the forces acting on the balls were calculated using traditional ball milling as simulated by DEM. The effect of the operational variables such as the rotational speed, ball material and size on the flow velocity, collision force and total impact energy were analyzed. The results showed that increased rotation speed with interaction impact energy between balls and balls, balls and pots and walls and balls. The rotation speed increases with an increase of the impact energy. Experiments were conducted to quantify the grinding performance under the same conditions. Furthermore, the results showed that ball motion affects the particle morphology, which changed from irregular type to plate type with increasing rotation speed. The evolution was also found to depend on the impact energy increase of the grinding media. These findings are useful to understand and optimize the particle motion and grinding behavior of traditional ball mills.

In efforts to characterize and understand the properties and processing of phenylethynylterminated imide (LaRC PETI-5, simply referred to as PETI-5) oligomers and polymers as a high-temperature sizing material for carbon fiber-reinforced polymer matrix composites, PETI-5 imidization and thermal curing behaviors have been extensively investigated based on the phenylethynyl end-group reaction. These studies are reviewed here. In addition, the use of PETI-5 to enhance interfacial adhesion between carbon fibers and a bismaleimide (BMI) matrix, as well as the dynamic mechanical properties of carbon/BMI composites, are discussed. Reports on the thermal expansion behavior of intercalated graphite flake, and the effects of exfoliated graphite nanoplatelets (xGnP) on the properties of PETI-5 matrix composites are also reviewed. The dynamic mechanical and thermal properties and the electrical resistivity of xGnP/PETI-5 composites are characterized. The effect of liquid rubber amine-terminated poly(butadiene-co-acrylonitrile) (ATBN)-coated xGnP particles incorporated into epoxy resin on the toughness of xGnP/epoxy composites is examined in terms of its impact on Izod strength. This paper provides an extensive overview from fundamental studies on PETI-5 and xGnP, as well as applied studies on relevant composite materials.

A sintered body of TiB2-reinforced iron matrix composite (Fe-TiB2) is fabricated by pressureless-sintering of a mixture of titanium hydride (TiH2) and iron boride (FeB) powders. The powder mixture is prepared in a planetary ball-mill at 700 rpm for 3 h and then pressurelessly sintered at 1300, 1350 and 1400oC for 0-2 h. The optimal sintering temperature for high densities (above 95% relative density) is between 1350 and 1400oC, where the holding time can be varied from 0.25 to 2 h. A maximum relative density of 96.0% is obtained from the (FeB+TiH2) powder compacts sintered at 1400oC for 2 h. Sintered compacts have two main phases of Fe and TiB2 along with traces of TiB, which seems to be formed through the reaction of TiB2 formed at lower temperatures during the heating stage with the excess Ti that is intentionally added to complete the reaction for TiB2 formation. Nearly fully densified sintered compacts show a homogeneous microstructure composed of fine TiB2 particulates with submicron sizes and an Fe-matrix. A maximum hardness of 71.2 HRC is obtained from the specimen sintered at 1400oC for 0.5 h, which is nearly equivalent to the HRC of conventional WC-Co hardmetals containing 20 wt% Co.

Graphene oxide (GO) powder processed by Hummer's method is mixed with p-type Bi2Te3 based thermoelectric materials by a high-energy ball milling process. The synthesized GO-dispersed p-type Bi2Te3 composite powder has a composition of Bi0.5Sb1.5Te3 (BSbT), and the powder is consolidated into composites with different contents of GO powder by using the spark plasma sintering (SPS) process. It is found that the addition of GO powder significantly decreases the thermal conductivity of the pure BSbT material through active phonon scattering at the newly formed interfaces. In addition, the electrical properties of the GO/BSbT composites are degraded by the addition of GO powder except in the case of the 0.1 wt% GO/BSbT composite. It is found that defects on the surface of GO powder hinder the electrical transport properties. As a result, the maximum thermoelectric performance (ZT value of 0.91) is achieved from the 0.1% GO/BSbT composite at 398 K. These results indicate that introducing GO powder into thermoelectric materials is a promising method to achieve enhanced thermoelectric performance due to the reduction in thermal conductivity.

The purpose of this experiment was designed to investigate the effects of medicinal herbs (MH) extracts on dementia induced by trimethyltin chloride (TMT) in rats. Six-week-old male Sprague-Dawley rats were randomly divided into five groups; normal group (group 1), control group (group 2), MH extracts group (250, 500 mg/kg) (group 3, group 4) and positive control group (tacrine group, group 5). In the control group to induce dementia, a 2.5 mg/kg of TMT intraperitoneal injection was used for 14 days (1 per day) in the rats. In the MH extracts group 250 mg/kg and 500 mg/kg of MH extracts were medicated in an oral inoculation for 20 days (1 per day). After 30 minutes, a 2.5 mg/kg of TMT intraperitoneal injection, which causes dementia, was used for 14 days (1 per day). In the positive control group (Tacrine group) 10 mg/kg of Tacrine, the dementia treatment, was medicated in an oral inoculation. After 30 mintues, 1 mg/kg of TMT intraperitoneal injection, which causes dementia, was used for 14 days (1 per day). The present author observed the passive avoidance performance test, and memory ability test (Y maze test), the values of MDA, acetlycholinesterase (AchE) activity in the brain and antioxidant enzyme in serum. MH extracts significantly improved memory of AD model rats in the Y-maze test, and also significantly improved memory of AD model rats in the passive avoidance test. MH extracts significantly reduced AChE activity, and significantly increased the SOD level, but not catalase and MDA. From the results above, MH extracts is thought to be effective in the improvement of antioxidant enzymes and memory ability.

Metal matrix composites(MMC) can obtain mechanical characteristics of application purposes that a single material is difficult to obtain. Al2 O3/AC8A composites were fabricated by low pressure infiltration process. The purpose is establishing the optimal casting conditions for composite preparation under low pressure. It is known the inorganic binder help infiltration. Therefore Al2O3 fiber preform's optimum sinter temperature is 1160℃, added inorganic binder is mixed binder(SiO2 sol:Al2O3 sol=5:2). And three fibers have been compared (Al2O3 80%/SiO2 20%, Al2O3 80%/SiO2 10% and Al2O3 97%/SiO2 3%). Al2O3/AC8A composites was made by each melting temperatures(650℃, 700℃, 750℃) and wear test was performed about effect of temperatures, kind of fiber, matrix and composites, aging time. Wear test is Ball on disk wear test. The resistance increased with the low melting temperature and Al2O3 80%/SiO2 20% fiber.

Cu-30 vol% SiC composites with relatively densified microstructure and a sound interface between the Cu and SiC phases were obtained by pressureless sintering of PCS-coated SiC and Cu powders. The coated SiC powders were prepared by thermal curing and pyrolysis of PCS. Thermal curing at 200 oC was performed to fabricate infusible materials prior to pyrolysis. The cured powders were heated treated up to 1600 oC for the pyrolysis process and for the formation of SiC crystals on the surface of the SiC powders. XRD analysis revealed that the main peaks corresponded to the α-SiC phase; peaks for β-SiC were newly appeared. The formation of β-SiC is explained by the transformation of thermally-cured PCS on the surface of the initial α-SiC powders. Using powder mixtures of coated SiC powder, hydrogen-reduced Cu-nitrate, and elemental Cu powders, Cu-SiC composites were fabricated by pressureless sintering at 1000 oC. Microstructural observation for the sintered composites showed that the powder mixture of PCS-coated SiC and Cu exhibited a relatively dense and homogeneous microstructure. Conversely, large pores and separated interfaces between Cu and SiC were observed in the sintered composite using uncoated SiC powders. These results suggest that Cu-SiC composites with sound microstructure can be prepared using a PCS coated SiC powder mixture.

Octahedral Co3O4/carbon nanofiber (CNF) composites are fabricated using electrospinning and hydrothermal methods. Their morphological characteristics, chemical bonding states, and electrochemical properties are used to demonstrate the improved photovoltaic properties of the samples. Octahedral Co3O4 grown on CNFs is based on metallic Co nanoparticles acting as seeds in the CNFs, which seeds are directly related to the high performance of DSSCs. The octahedral Co3O4/CNFs composites exhibit high photocurrent density (12.73 mA/m2), superb fill factor (62.1 %), and excellent power conversion efficiency (5.61 %) compared to those characteristics of commercial Co3O4, conventional CNFs, and metallic Co-seed/CNFs. These results can be described as stemmnig from the synergistic effect of the porous and graphitized matrix formed by catalytic graphitization using the metal cobalt catalyst on CNFs, which leads to an increase in the catalytic activity for the reduction of triiodide ions. Therefore, octahedral Co3O4/CNFs composites can be used as a counter electrode for Pt-free dye-sensitized solar cells.

The effect of CNT diameters on properties of CNT-polyamide composites was investigated such as electrical conductivity, tensile strength and thermal conductivity. To get different diameter distributions of CNTs, several portions of Mo and Fe in Mo-Fe/MgO catalysts were synthesized by a combustion method at 600℃. And all CNTs growed at 900℃ with 3 SLM methane and 1 SLM hydrogen for 40min. Four kinds of CNTs with different diameter distributions, such as 1~3nm, 3~7nm, 7~13nm, and 10~30nm, were selected to make CNT-polyamide composites. Each composite was manufactured by a solution mixing using bar-type ultra-sonicator in the CNT portions from 1phr to 50phr. And electrical conductivity, tensile strength, and thermal conductivity were measured. Three properties of CNT-polyamide composite, manufactured with 10nm diameter, were more excellent compared to other composites, with electrical conductivity  Ω at 7phr, thermal conductivity 2.4.W/mK at 40phr, tensile strength 60MPa at 30phr. CNTs with a diameter of 10nm were superior to other diameters for the multi-functional composite such as CNT-polyamide composites.

Ni and Ni-Cr reinforced Al alloy (AC8A) composites were fabricated by low pressure infiltration process. Porous Ni was applied as preform. Ni reinforced AC8A composites were fabricated under 0.3 MPa at 650, 700 and 750 degrees centigrade, respectively, while Ni-Cr reinforced AC8A composites were fabricated under low pressure limited to the maximum of 0.5 Mpa at 750, 800 and 850 degrees centigrade, respectively. Microstructure and phase composition of the composites were evaluated by optical microscope, X-Ray diffraction (XRD), electro-probe micro analyzer (EMPA). Intermetallic compounds Al3Ni and CrSi were observed in the composites. The results indicate that the grain size has been increasing with the increase of the infiltration temperatures. However, the wear resistance of Ni/AC8A and Ni-Cr AC8A peaked at 650 degree centigrade and 800 degrees centigrade, respectively. In addition, based on the wear characteristics and wear surfaces, Ni-Cr/AC8A composites have a better wear resistance than Ni/AC8A composites and AC8A.

Carbon nanofiber (CNF) composites coated with spindle-shaped Fe2O3 nanoparticles (NPs) are fabricated by a combination of an electrospinning method and a hydrothermal method, and their morphological, structural, and chemical properties are measured by field-emission scanning electron microscopy, transmission electron microscopy, Xray diffraction, and X-ray photoelectron spectroscopy. For comparison, CNFs and spindle-shaped Fe2O3 NPs are prepared by either an electrospinning method or a hydrothermal method, respectively. Dye-sensitized solar cells (DSSCs) fabricated with the composites exhibit enhanced open circuit voltage (0.70 V), short-circuit current density (12.82 mA/cm2), fill factor (61.30%), and power conversion efficiency (5.52%) compared to those of the CNFs (0.66 V, 11.61 mA/cm2, 51.96%, and 3.97%) and spindle-shaped Fe2O3 NPs (0.67 V, 11.45 mA/cm2, 50.17%, and 3.86%). This performance improvement can be attributed to a synergistic effect of a superb catalytic reaction of spindle-shaped Fe2O3 NPs and efficient charge transfer relative to the one-dimensional nanostructure of the CNFs. Therefore, spindle-shaped Fe2O3-NPcoated CNF composites may be proposed as a potential alternative material for low-cost counter electrodes in DSSCs.

In the present study, exfoliated graphite nanoplatelets (xGnP) with different particle sizes were coated onto polyacrylonitrile-based carbon fibers by a direct coating method. The flexural properties, interlaminar shear strength, and the morphology of the xGnP-coated carbon fiber/phenolic matrix composites were investigated in terms of their longitudinal flexural strength and modulus, interlaminar shear strength, and by optical and scanning electron microscopic observations. The results were compared with a phenolic matrix composite counterpart prepared without xGnP. The flexural properties and interlaminar shear strength of the xGnP-coated carbon fiber/phenolic matrix composites were found to be higher than those of the uncoated composite. The flexural and interlaminar shear strengths were affected by the particle size of the xGnP, while the particle size had no significant effect on the flexural modulus. It seems that the interfacial contacts between the xGnP-coated carbon fibers and the phenolic matrix play a role in enhancing the flexural strength as well as the interlaminar shear strength of the composites.