In this study, we demonstrate the enhancement in thermal stability of polyoxymethylene (POM)-based biopolymer blend materials. Polyoxymethylene (POM)/Polylactic acid (PLA) blends have been used as alternative biopolym...In this study, we demonstrate the enhancement in thermal stability of polyoxymethylene (POM)-based biopolymer blend materials. Polyoxymethylene (POM)/Polylactic acid (PLA) blends have been used as alternative biopolymer materials for supporting environmental problems with thermal stability feature. The effects on POM biopolymer blend materials with a controlled PLA amount in their compositions under various injection conditions, were investigated by thermogravimetric analysis, dynamic mechanical analysis, and differential scanning calorimetry. The POM/PLA biopolymer blend materials showed POM phase acted as a homogeneous nucleating site for increasing PLA crystallization, which improves storage modulus of the blend materials. The decomposition temperatures of POM/PLA biopolymer blends tend to shift around 30˚C - 50˚C lower compared to the decomposition temperatures of PLA. Thus, the decomposition temperature behavior of POM/PLA blends seems to be closer to POM. The suitable ratio in POM70/PLA30 resulted in the high strength of the blend materials. The POM/PLA biopolymer blend material was tested at various injection speeds and good miscibility was obtained at an injection speed of 100 mm/s. This enhancement of thermal stability in POM/PLA blend materials should be useful in the development of high-performance bio-based thermoplastic materials.展开更多
This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic ...This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic resin (GF/PF). The CF/Epoxy was placed in the mold cavity prior to injecting GF/PF onto the inserted injection molded CF/Epoxy specimens. The role of adhesion between the inserted part and injected resin on the mechanical properties was evaluated by 3 point bending and impact tests. In addition, the effect of prepreg orientation on the mechanical properties of the prepreg inserted-injection molding system was investigated. It was found that the prepreg with unidirectional orientation significantly improved flexural and impact strength of the inserted injection molding composites, providing better support and resistance to bending and impact loading. The main failure modes of the specimens were structural and adhesive failure.展开更多
In this work, the generalizing of the finite element method (FEM) of thermoplastic prepreg insert injection molding composites was investigated. The specimens were prepared using glass fiber/polyamidc 6 (GF/PA6) inser...In this work, the generalizing of the finite element method (FEM) of thermoplastic prepreg insert injection molding composites was investigated. The specimens were prepared using glass fiber/polyamidc 6 (GF/PA6) inserted prepreg, and their characteristics were investigated and compared under ANSYS workbench program. The prediction of the bending initial fracture point under analytical tensile testing with interlayer on prepreg insert moldings was focused. It was found that the bending initial fracture point was applied to predict by matching the shear stress. There was obtained from analytical tensile testing and bending analysis. Therefore, it can be obtained the optimum of the clastic modulus ratio on the injection part/interlayer/insert part by using FEM via ANSYS workbench.展开更多
Recycled PET (R-PET) is well known to exhibit brittle behavior in the presence of notches and indicated the low heat distortion temperature. In addition, it is hard to prevent some impurities such as cap or label of t...Recycled PET (R-PET) is well known to exhibit brittle behavior in the presence of notches and indicated the low heat distortion temperature. In addition, it is hard to prevent some impurities such as cap or label of the bottle that mixed into R-PET during the recycling process. In this paper, the effect of the amounts and kinds of compatibilizers on the morphological characteristics and mechanical performance of recycled poly(ethylene terephthalate) (R-PET) compounded with polyethylene (PE), polypropylene (PP), and polystyrene (PS) was investigated. From the results, with an increase in the glycidyl methacrylate modified PE (EGMA) additive contents, in the increment of the Izod impact strength of Composite-G was obtained. In addition, it was found that the miscibility of Composite-G was improved with increasing the amount of EGMA, which indicated from the result of SEM images.展开更多
Short Retraction Notice The paper does not meet the standards of "Open Journal of Composite Materials". This article has been retracted to straighten the academic record. In making this decision the Editoria...Short Retraction Notice The paper does not meet the standards of "Open Journal of Composite Materials". This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. The aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused. Editor guiding this retraction: Prof. Chengye Fan (EiC of OJCM) The full retraction notice in PDF is preceding the original paper, which is marked "Withdraw".展开更多
In this study, a numerical method was proposed to evaluate the calligraphy work called calligraphy evaluation system. Four classical chirographies of ＂Kaisho＂, ＂Gyosho＂, ＂Sousho＂ and ＂Hiragana＂, and 47 charact...In this study, a numerical method was proposed to evaluate the calligraphy work called calligraphy evaluation system. Four classical chirographies of ＂Kaisho＂, ＂Gyosho＂, ＂Sousho＂ and ＂Hiragana＂, and 47 characters for each chirography, were selected and analyzed by this system. The ＂Sumi＂ distribution of character was clarified from 12 directions and summarized into four parts of horizontal part, diagonal left part, vertical part and diagonal fight part. The character＇s contour line was converted to a signal data in order to calculate roundness index. The degree of character＇s radian was presented by roundness index. The smooth index was calculated at the same time. Additionally, width index, ＂Sumi＂ ratio, stability index also were calculated to contrast the features of each style. The main character points of four styles of ＂Kaisho＇, ＂Gyosho＂, ＂Sousho＂, ＂Hiragana＂ were extracted to compare each other, and provide a reference for learners. The learners could obtain the quantitative data to understand their work＇s characteristics. It can also be compared with other person＇s work by this system in order to improve learners＇ writing skill.展开更多
In this paper, investigation on the initial fracture behavior was carried out on roving glass woven fabric reinforced composites which were manufactured by hand lay-up method. Two kinds of roving glass woven fabrics o...In this paper, investigation on the initial fracture behavior was carried out on roving glass woven fabric reinforced composites which were manufactured by hand lay-up method. Two kinds of roving glass woven fabrics of different FAW (Fabric Area Weight) and crimp ratio, Type A of 570 g/m2 and Type B of 800 g/m2, were adopted as reinforcement in this study. Tensile test was conducted and tensile properties were discussed on specimens of 6 degrees 0°/5°/10°/80°/85°/90°. The initial fracture behavior was observed on 0 degree and 90 degree and the fracture mechanism was compared and discussed among 5°/10°/80°/85°. The results showed that Type B has higher tensile modulus and tensile strength than that of Type A. And different initial fracture behaviors between two kinds of materials was observed and analyzed, which indicated that the crimp ratio plays an important role of woven fabric reinforced composites in fracture mechanism.展开更多
This article presents an experimental study that clarifies the relationship between the initial fracture stress and fatigue limit of glass fiber reinforced unsaturated polyester resin specimens with a laminated struct...This article presents an experimental study that clarifies the relationship between the initial fracture stress and fatigue limit of glass fiber reinforced unsaturated polyester resin specimens with a laminated structure taken from a pultruded square pipe. Quasi-static bending and tension tests are performed with acoustic emission (AE) measurements to identifying the occurrence of initial fracture during testing. AE and observation results have clarified the occurrence of initial fracture was detected by maximum acoustic energy values and corresponding fiber breakage in the unidirectional (UD) bundles. Moreover, the ratio of initial fracture stress to ultimate strength is 32% in bending and 26% in tension, when comparing stress and strains on the tension side of the UD layer. These values are in good agreement with each other and with the measured tensile fatigue limit when the cyclic stress is at 25% of the tensile strength. Initial fracture stress obtained by static tests is close values to the fatigue limit which will greatly contribute to the prediction of the fatigue limit.展开更多
Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. Currently, there exist only two companies that manufacture metal powder for the purpose of Maki-e, and this...Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. Currently, there exist only two companies that manufacture metal powder for the purpose of Maki-e, and this research focuses on comparing the material characteristics of the gold powders with round shape manufactured by them. EDS (energy-dispersive X-ray spectroscopy) analysis, image analysis of particle shape before and after Maki-e processing, and color analysis of samples after Maki-e processing were carried out in this research. The study revealed that current gold powders with round shape had almost the same content ratio regardless of the manufacturing company and the powder diameter. In addition, spherical shape and irregular shape were observed in any gold powders, and the aggregates were observed in powder with increasing the powder diameter, while the shape of the aggregates differed with manufacturing companies. Therefore, it was indicated that the aggregates in the powder made by Asano Co., Ltd. had an influence on the particle diameter and its deviation after Maki-e processing. Moreover, the powder in Urushi resin has an influence on the Maki-e appearance because there is a color difference in polished powder, powder in Urushi resin, and Urushi resin.展开更多
Many researchers have shown interest in the reinforcement of commodity thermoplastic with natural fibers. However, the drawback of natural fibers is their low thermal processing temperatures, that border around 200℃....Many researchers have shown interest in the reinforcement of commodity thermoplastic with natural fibers. However, the drawback of natural fibers is their low thermal processing temperatures, that border around 200℃. In this investigation, we tried to improve the thermal stability of natural fibers with the use of flexible epoxy surface coating that could facilitate processing with engineering thermoplastics. Jute fabric and Polyamide 6 (PA6) composites were prepared by compression molding. The thermal decomposition characteristics of the jute fabric were evaluated by using thermo gravimetric analysis (TGA). Mechanical analysis was conducted to evaluate tensile test and three point bending test of composite. It was found that thermal degradation resistance of jute fabric was improved by coating with flexible epoxy resin. Moreover, the flexural modulus improved with increasing curative concentration. The interfacial interaction between the epoxy and PA6 was clearly indicated by the photo micrographs of the polished cross sections of the coated and uncoated jute fabric/PA6 composites.展开更多
This paper focuses on Byakudan-nuri, one of the traditional decoration techniques of Japanese Urushi (Urushi natural lacquer) crafts. Works produced by Byakudan-nuri express a unique luster color owing to painting gol...This paper focuses on Byakudan-nuri, one of the traditional decoration techniques of Japanese Urushi (Urushi natural lacquer) crafts. Works produced by Byakudan-nuri express a unique luster color owing to painting gold or silver leaves along with highly transparent Urushi. The specific problem of Byakudan-nuri is the exfoliation of Urushi off the metal leaf surface, to solve a lot of repair work which is done nowadays. For Byakudan-nuri, silver leaf is preferred to a gold leaf. This paper tries to clarify the influence of the different kinds of metal leaves on the appearance and peel strength of works of Byakudan-nuri and, moreover, to elucidate the reason why silver leaf has been used more frequently for Byakudan-nuri until now. It was found out that the reason for the more frequent use of silver leaf in Byakudan-nuri is that silver does not seem to affect the appearance and peel strength in works produced by this technique.展开更多
Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. In 2014, there exist only two companies that manufacture silver powder for the purpose of Maki-e, and this ...Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. In 2014, there exist only two companies that manufacture silver powder for the purpose of Maki-e, and this study focuses on comparing the powders manufactured by them. Gloss and color of each silver powder were measured after Maki-e decoration was finished, and EDS (energy-dispersive X-ray spectroscopy) was used to determine the differences in their chemical composition. In addition, to verify the effect of polishing, residual gloss after sulfuration and polishing was measured. The study revealed that the shapes of the silver powders (Maru-fun, No. 1) manufactured by the two companies are different and it affects the occupancy rate of Urushi and powder, which in turn affects their gloss and color. Wakou silver has a very strong resistance to sulfuration;however, owing to its Pd content, its chroma is much lower than that of other powders. It was shown that sulfuration on powder surface can be removed by polishing irrespective of the shape and chemical composition ratio of the particles.展开更多
Recently, nanostructures such as nanocrystals and nanoaggregates have attracted much attention in many quarters of materials, electronics, and biology to create higher-value-added functional nanoscale materials and fi...Recently, nanostructures such as nanocrystals and nanoaggregates have attracted much attention in many quarters of materials, electronics, and biology to create higher-value-added functional nanoscale materials and films. In this research, the fabrication of nanoaggregates on ultrathin photoconductive films of poly(N-vinylcarbazole) (PVCz) by applying thermal treatment is demonstrated. The structure and size are discussed on the basis of the results of atomic force microscope images. As a result, after thermal treatment of these films above the glass transition temperature (Tg) of PVCz, different types of surface morphological changes were induced showing a dependence on the tacticity of PVCz. Radically polymerized PVCz(r) ultrathin film showed small aggregates with heights of ~8 nm on the film surface after thermal treatment, while cationically polymerized PVCz(c), which has higher isotactic diad fractions than PVCz(r), indicated similar aggregates on the film surface, although the number of aggregates was smaller than PVCz(r). It is considered that these different phenomena depend on the tacticity of PVCz and the interaction between PVCz molecules and the substrate surface.展开更多
Effects of ultrasonic vibrations on mechanical properties of fiber reinforced plastics were investigated during molding resin impregnation process in vacuum assisted resin transfer molding.?The vacuum bag including th...Effects of ultrasonic vibrations on mechanical properties of fiber reinforced plastics were investigated during molding resin impregnation process in vacuum assisted resin transfer molding.?The vacuum bag including the preformed each?non-crimp fabrics (carbon and glass fibers)?was placed in a water bath of an ultrasonic wave generator during resin impregnation. The mechanical properties of the laminates were evaluated?through the mechanical strength tests and scanning electron microscope?(SEM) observation. The results revealed that ultrasonic waves improved transverse tensile, flexural, interlaminar shear, and compressive strengths of the carbon fiber (CF) laminates and interlaminar shear and compressive strengths of the glass fiber (GF) laminates. It was found from SEM observation that the fracture modes of the CF and GF laminates processed using ultrasonic waves were resin fracture. Accordingly, the adhesion of the fiber/resin interface was improved by oscillating ultrasonic vibration during resin impregnation, leading to an increase of the interface strength.展开更多
In this study, the adsorptive properties of L-menthol, moisture vapor transmission rate, and mechanical properties of poly (ethylene terephthalate) (PET), polypropylene (PP), and their blends were evaluated in contain...In this study, the adsorptive properties of L-menthol, moisture vapor transmission rate, and mechanical properties of poly (ethylene terephthalate) (PET), polypropylene (PP), and their blends were evaluated in containers fabricated by injection molding without a compatibilizing agent. These containers intended to hold pharmaceutical solutions containing lipophilic chemicals such as L-menthol. By the addition of a small amount of PP, the moisture barrier properties of PET were effectively improved, but its anti-adsorptive property was reduced. The strength of the PET/PP blends was reduced, but some PET/PP blends were still able to bear the experimental load required for application in eye-drop containers. PET/PP = 9/1 and PET/PP = 8/2 were found to be most applicable for using in the fabrication of containers for medicinal solutions.展开更多
In this paper, woven fabrics of glass fiber/carbon fiber intra-hybrid in plain structure were used to fabricate fiber reinforced plastic (FRP) composite by hand lay-up method. The investigation on tensile property was...In this paper, woven fabrics of glass fiber/carbon fiber intra-hybrid in plain structure were used to fabricate fiber reinforced plastic (FRP) composite by hand lay-up method. The investigation on tensile property was carried out on specimens in 7 orientations including 0°/5°/15°/75°/85°/90° in previous works. With the specimen parameters and experimental data, FEM model was built by the software of Marc. By combining the experimental results and finite element analysis, the modulus was simulated and calculated at the first stage. Then interfacial stress of the 0 degree and 90 degree was also calculated. By the initial fracture stress data from experiment as well as the simulation value of interfacial strength of 0 and 90 degree, the initial fracture stress of the off-axial specimens wascalculated and predicted. The result shows that the interfacial strength of the glass fiber bundle is higher than that of the carbon fiber bundle in transverse direction. By using the interfacial strength and according to the Von Mises yielding criterion, the initial fracture stress was predicted, which can be a contribution to the design or predict of the material properties.展开更多
Reduction of dichlorosilanes with Mg metal in the presence of LiCl and Lewis acid such as FeCl2 or ZnCl2 was found to be the highly practical method for the synthesis of polysilanes (PS). This method is so useful and ...Reduction of dichlorosilanes with Mg metal in the presence of LiCl and Lewis acid such as FeCl2 or ZnCl2 was found to be the highly practical method for the synthesis of polysilanes (PS). This method is so useful and practical that PS can be prepared by stirring dichlorosilanes at room temperature. This method was successfully applied for the synthesis of various types of PS having a linear structure, a cyclic structure and silane-styrene copolymers as another type of PS. The structure of the reaction intermediates was also analyzed. At the initiation stage the results of FD-MS (Field desorption mass spectrometry) and GPC (Gel permeation chromatography) showed that linear oligomers were mainly formed by stepwise reactions, and then the high polymers and cyclic oligomers were formed in parallel.展开更多
This paper explores quasi-static flexural properties and fracture behavior of a pultruded glass fiber/unsaturated polyester square pipe for automotive structural applications. Three-point flexural testing is performed...This paper explores quasi-static flexural properties and fracture behavior of a pultruded glass fiber/unsaturated polyester square pipe for automotive structural applications. Three-point flexural testing is performed in an Instron Universal Testing Machine with steel jigs supporting the top and bottom surfaces of the pipe. Acoustic emission (AE) measurements are recorded during flexural testing to evaluate initial fracture in the pipe structure. After final fracture, five cross-sections of the pipe are cut at 50-mm intervals along the longitudinal axis, with the first cut located at the mid-span of the pipe. Cross-sections of a pipe from an interrupted test where initial fracture is detected from the AE method are also prepared. Damage locations and behavior on each cross-section are observed. The flexural testing results show that the cumulative AE counts increase rapidly from 2.5 kN, that final failure occurs at a maximum load of approximately 13 kN, and that corresponding initial and final failure occurs in the two corner regions on the compressive side of flexural loading. Failure initiates by stress concentrations due to the upper jig on the top surface during bending. The cross-sectional observations also reveal clear deformation behavior of the pipe where failure is present, marked by inward bending of the top surface and upper corners located on the compressive side, near the jig. The locations of maximum stresses and deformations obtained from finite element analysis of this pipe structure are in very good agreement with the experimental observations.展开更多
文摘In this study, we demonstrate the enhancement in thermal stability of polyoxymethylene (POM)-based biopolymer blend materials. Polyoxymethylene (POM)/Polylactic acid (PLA) blends have been used as alternative biopolymer materials for supporting environmental problems with thermal stability feature. The effects on POM biopolymer blend materials with a controlled PLA amount in their compositions under various injection conditions, were investigated by thermogravimetric analysis, dynamic mechanical analysis, and differential scanning calorimetry. The POM/PLA biopolymer blend materials showed POM phase acted as a homogeneous nucleating site for increasing PLA crystallization, which improves storage modulus of the blend materials. The decomposition temperatures of POM/PLA biopolymer blends tend to shift around 30˚C - 50˚C lower compared to the decomposition temperatures of PLA. Thus, the decomposition temperature behavior of POM/PLA blends seems to be closer to POM. The suitable ratio in POM70/PLA30 resulted in the high strength of the blend materials. The POM/PLA biopolymer blend material was tested at various injection speeds and good miscibility was obtained at an injection speed of 100 mm/s. This enhancement of thermal stability in POM/PLA blend materials should be useful in the development of high-performance bio-based thermoplastic materials.
文摘This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic resin (GF/PF). The CF/Epoxy was placed in the mold cavity prior to injecting GF/PF onto the inserted injection molded CF/Epoxy specimens. The role of adhesion between the inserted part and injected resin on the mechanical properties was evaluated by 3 point bending and impact tests. In addition, the effect of prepreg orientation on the mechanical properties of the prepreg inserted-injection molding system was investigated. It was found that the prepreg with unidirectional orientation significantly improved flexural and impact strength of the inserted injection molding composites, providing better support and resistance to bending and impact loading. The main failure modes of the specimens were structural and adhesive failure.
文摘In this work, the generalizing of the finite element method (FEM) of thermoplastic prepreg insert injection molding composites was investigated. The specimens were prepared using glass fiber/polyamidc 6 (GF/PA6) inserted prepreg, and their characteristics were investigated and compared under ANSYS workbench program. The prediction of the bending initial fracture point under analytical tensile testing with interlayer on prepreg insert moldings was focused. It was found that the bending initial fracture point was applied to predict by matching the shear stress. There was obtained from analytical tensile testing and bending analysis. Therefore, it can be obtained the optimum of the clastic modulus ratio on the injection part/interlayer/insert part by using FEM via ANSYS workbench.
文摘Recycled PET (R-PET) is well known to exhibit brittle behavior in the presence of notches and indicated the low heat distortion temperature. In addition, it is hard to prevent some impurities such as cap or label of the bottle that mixed into R-PET during the recycling process. In this paper, the effect of the amounts and kinds of compatibilizers on the morphological characteristics and mechanical performance of recycled poly(ethylene terephthalate) (R-PET) compounded with polyethylene (PE), polypropylene (PP), and polystyrene (PS) was investigated. From the results, with an increase in the glycidyl methacrylate modified PE (EGMA) additive contents, in the increment of the Izod impact strength of Composite-G was obtained. In addition, it was found that the miscibility of Composite-G was improved with increasing the amount of EGMA, which indicated from the result of SEM images.
文摘Short Retraction Notice The paper does not meet the standards of "Open Journal of Composite Materials". This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. The aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused. Editor guiding this retraction: Prof. Chengye Fan (EiC of OJCM) The full retraction notice in PDF is preceding the original paper, which is marked "Withdraw".
文摘In this study, a numerical method was proposed to evaluate the calligraphy work called calligraphy evaluation system. Four classical chirographies of ＂Kaisho＂, ＂Gyosho＂, ＂Sousho＂ and ＂Hiragana＂, and 47 characters for each chirography, were selected and analyzed by this system. The ＂Sumi＂ distribution of character was clarified from 12 directions and summarized into four parts of horizontal part, diagonal left part, vertical part and diagonal fight part. The character＇s contour line was converted to a signal data in order to calculate roundness index. The degree of character＇s radian was presented by roundness index. The smooth index was calculated at the same time. Additionally, width index, ＂Sumi＂ ratio, stability index also were calculated to contrast the features of each style. The main character points of four styles of ＂Kaisho＇, ＂Gyosho＂, ＂Sousho＂, ＂Hiragana＂ were extracted to compare each other, and provide a reference for learners. The learners could obtain the quantitative data to understand their work＇s characteristics. It can also be compared with other person＇s work by this system in order to improve learners＇ writing skill.
文摘In this paper, investigation on the initial fracture behavior was carried out on roving glass woven fabric reinforced composites which were manufactured by hand lay-up method. Two kinds of roving glass woven fabrics of different FAW (Fabric Area Weight) and crimp ratio, Type A of 570 g/m2 and Type B of 800 g/m2, were adopted as reinforcement in this study. Tensile test was conducted and tensile properties were discussed on specimens of 6 degrees 0°/5°/10°/80°/85°/90°. The initial fracture behavior was observed on 0 degree and 90 degree and the fracture mechanism was compared and discussed among 5°/10°/80°/85°. The results showed that Type B has higher tensile modulus and tensile strength than that of Type A. And different initial fracture behaviors between two kinds of materials was observed and analyzed, which indicated that the crimp ratio plays an important role of woven fabric reinforced composites in fracture mechanism.
文摘This article presents an experimental study that clarifies the relationship between the initial fracture stress and fatigue limit of glass fiber reinforced unsaturated polyester resin specimens with a laminated structure taken from a pultruded square pipe. Quasi-static bending and tension tests are performed with acoustic emission (AE) measurements to identifying the occurrence of initial fracture during testing. AE and observation results have clarified the occurrence of initial fracture was detected by maximum acoustic energy values and corresponding fiber breakage in the unidirectional (UD) bundles. Moreover, the ratio of initial fracture stress to ultimate strength is 32% in bending and 26% in tension, when comparing stress and strains on the tension side of the UD layer. These values are in good agreement with each other and with the measured tensile fatigue limit when the cyclic stress is at 25% of the tensile strength. Initial fracture stress obtained by static tests is close values to the fatigue limit which will greatly contribute to the prediction of the fatigue limit.
文摘Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. Currently, there exist only two companies that manufacture metal powder for the purpose of Maki-e, and this research focuses on comparing the material characteristics of the gold powders with round shape manufactured by them. EDS (energy-dispersive X-ray spectroscopy) analysis, image analysis of particle shape before and after Maki-e processing, and color analysis of samples after Maki-e processing were carried out in this research. The study revealed that current gold powders with round shape had almost the same content ratio regardless of the manufacturing company and the powder diameter. In addition, spherical shape and irregular shape were observed in any gold powders, and the aggregates were observed in powder with increasing the powder diameter, while the shape of the aggregates differed with manufacturing companies. Therefore, it was indicated that the aggregates in the powder made by Asano Co., Ltd. had an influence on the particle diameter and its deviation after Maki-e processing. Moreover, the powder in Urushi resin has an influence on the Maki-e appearance because there is a color difference in polished powder, powder in Urushi resin, and Urushi resin.
文摘Many researchers have shown interest in the reinforcement of commodity thermoplastic with natural fibers. However, the drawback of natural fibers is their low thermal processing temperatures, that border around 200℃. In this investigation, we tried to improve the thermal stability of natural fibers with the use of flexible epoxy surface coating that could facilitate processing with engineering thermoplastics. Jute fabric and Polyamide 6 (PA6) composites were prepared by compression molding. The thermal decomposition characteristics of the jute fabric were evaluated by using thermo gravimetric analysis (TGA). Mechanical analysis was conducted to evaluate tensile test and three point bending test of composite. It was found that thermal degradation resistance of jute fabric was improved by coating with flexible epoxy resin. Moreover, the flexural modulus improved with increasing curative concentration. The interfacial interaction between the epoxy and PA6 was clearly indicated by the photo micrographs of the polished cross sections of the coated and uncoated jute fabric/PA6 composites.
文摘This paper focuses on Byakudan-nuri, one of the traditional decoration techniques of Japanese Urushi (Urushi natural lacquer) crafts. Works produced by Byakudan-nuri express a unique luster color owing to painting gold or silver leaves along with highly transparent Urushi. The specific problem of Byakudan-nuri is the exfoliation of Urushi off the metal leaf surface, to solve a lot of repair work which is done nowadays. For Byakudan-nuri, silver leaf is preferred to a gold leaf. This paper tries to clarify the influence of the different kinds of metal leaves on the appearance and peel strength of works of Byakudan-nuri and, moreover, to elucidate the reason why silver leaf has been used more frequently for Byakudan-nuri until now. It was found out that the reason for the more frequent use of silver leaf in Byakudan-nuri is that silver does not seem to affect the appearance and peel strength in works produced by this technique.
文摘Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. In 2014, there exist only two companies that manufacture silver powder for the purpose of Maki-e, and this study focuses on comparing the powders manufactured by them. Gloss and color of each silver powder were measured after Maki-e decoration was finished, and EDS (energy-dispersive X-ray spectroscopy) was used to determine the differences in their chemical composition. In addition, to verify the effect of polishing, residual gloss after sulfuration and polishing was measured. The study revealed that the shapes of the silver powders (Maru-fun, No. 1) manufactured by the two companies are different and it affects the occupancy rate of Urushi and powder, which in turn affects their gloss and color. Wakou silver has a very strong resistance to sulfuration;however, owing to its Pd content, its chroma is much lower than that of other powders. It was shown that sulfuration on powder surface can be removed by polishing irrespective of the shape and chemical composition ratio of the particles.
文摘Recently, nanostructures such as nanocrystals and nanoaggregates have attracted much attention in many quarters of materials, electronics, and biology to create higher-value-added functional nanoscale materials and films. In this research, the fabrication of nanoaggregates on ultrathin photoconductive films of poly(N-vinylcarbazole) (PVCz) by applying thermal treatment is demonstrated. The structure and size are discussed on the basis of the results of atomic force microscope images. As a result, after thermal treatment of these films above the glass transition temperature (Tg) of PVCz, different types of surface morphological changes were induced showing a dependence on the tacticity of PVCz. Radically polymerized PVCz(r) ultrathin film showed small aggregates with heights of ~8 nm on the film surface after thermal treatment, while cationically polymerized PVCz(c), which has higher isotactic diad fractions than PVCz(r), indicated similar aggregates on the film surface, although the number of aggregates was smaller than PVCz(r). It is considered that these different phenomena depend on the tacticity of PVCz and the interaction between PVCz molecules and the substrate surface.
文摘Effects of ultrasonic vibrations on mechanical properties of fiber reinforced plastics were investigated during molding resin impregnation process in vacuum assisted resin transfer molding.?The vacuum bag including the preformed each?non-crimp fabrics (carbon and glass fibers)?was placed in a water bath of an ultrasonic wave generator during resin impregnation. The mechanical properties of the laminates were evaluated?through the mechanical strength tests and scanning electron microscope?(SEM) observation. The results revealed that ultrasonic waves improved transverse tensile, flexural, interlaminar shear, and compressive strengths of the carbon fiber (CF) laminates and interlaminar shear and compressive strengths of the glass fiber (GF) laminates. It was found from SEM observation that the fracture modes of the CF and GF laminates processed using ultrasonic waves were resin fracture. Accordingly, the adhesion of the fiber/resin interface was improved by oscillating ultrasonic vibration during resin impregnation, leading to an increase of the interface strength.
文摘In this study, the adsorptive properties of L-menthol, moisture vapor transmission rate, and mechanical properties of poly (ethylene terephthalate) (PET), polypropylene (PP), and their blends were evaluated in containers fabricated by injection molding without a compatibilizing agent. These containers intended to hold pharmaceutical solutions containing lipophilic chemicals such as L-menthol. By the addition of a small amount of PP, the moisture barrier properties of PET were effectively improved, but its anti-adsorptive property was reduced. The strength of the PET/PP blends was reduced, but some PET/PP blends were still able to bear the experimental load required for application in eye-drop containers. PET/PP = 9/1 and PET/PP = 8/2 were found to be most applicable for using in the fabrication of containers for medicinal solutions.
文摘In this paper, woven fabrics of glass fiber/carbon fiber intra-hybrid in plain structure were used to fabricate fiber reinforced plastic (FRP) composite by hand lay-up method. The investigation on tensile property was carried out on specimens in 7 orientations including 0°/5°/15°/75°/85°/90° in previous works. With the specimen parameters and experimental data, FEM model was built by the software of Marc. By combining the experimental results and finite element analysis, the modulus was simulated and calculated at the first stage. Then interfacial stress of the 0 degree and 90 degree was also calculated. By the initial fracture stress data from experiment as well as the simulation value of interfacial strength of 0 and 90 degree, the initial fracture stress of the off-axial specimens wascalculated and predicted. The result shows that the interfacial strength of the glass fiber bundle is higher than that of the carbon fiber bundle in transverse direction. By using the interfacial strength and according to the Von Mises yielding criterion, the initial fracture stress was predicted, which can be a contribution to the design or predict of the material properties.
文摘Reduction of dichlorosilanes with Mg metal in the presence of LiCl and Lewis acid such as FeCl2 or ZnCl2 was found to be the highly practical method for the synthesis of polysilanes (PS). This method is so useful and practical that PS can be prepared by stirring dichlorosilanes at room temperature. This method was successfully applied for the synthesis of various types of PS having a linear structure, a cyclic structure and silane-styrene copolymers as another type of PS. The structure of the reaction intermediates was also analyzed. At the initiation stage the results of FD-MS (Field desorption mass spectrometry) and GPC (Gel permeation chromatography) showed that linear oligomers were mainly formed by stepwise reactions, and then the high polymers and cyclic oligomers were formed in parallel.
文摘This paper explores quasi-static flexural properties and fracture behavior of a pultruded glass fiber/unsaturated polyester square pipe for automotive structural applications. Three-point flexural testing is performed in an Instron Universal Testing Machine with steel jigs supporting the top and bottom surfaces of the pipe. Acoustic emission (AE) measurements are recorded during flexural testing to evaluate initial fracture in the pipe structure. After final fracture, five cross-sections of the pipe are cut at 50-mm intervals along the longitudinal axis, with the first cut located at the mid-span of the pipe. Cross-sections of a pipe from an interrupted test where initial fracture is detected from the AE method are also prepared. Damage locations and behavior on each cross-section are observed. The flexural testing results show that the cumulative AE counts increase rapidly from 2.5 kN, that final failure occurs at a maximum load of approximately 13 kN, and that corresponding initial and final failure occurs in the two corner regions on the compressive side of flexural loading. Failure initiates by stress concentrations due to the upper jig on the top surface during bending. The cross-sectional observations also reveal clear deformation behavior of the pipe where failure is present, marked by inward bending of the top surface and upper corners located on the compressive side, near the jig. The locations of maximum stresses and deformations obtained from finite element analysis of this pipe structure are in very good agreement with the experimental observations.
