Biodegradation of PHBV/GNS nanocomposites by Penicillium funiculosum

Biodegradable polymer nanocomposites are an essential alternative to minimize the generation of polymeric solid waste that shows short shelf life and difficult degradation. In this study, nanocomposites based on poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) were prepared by the incorporation of different contents, 0.25, 0.50, 0.75, and 1.00 wt % of graphite nanosheets (GNS), using a solution casting method. The investigation of the PHBV samples biodegradation was made using filamentous fungi (Penicillium funiculosum) in solid medium. Characterization of the material was performed by weight loss, differential scanning calorimetry, carbonyl index determined by Fourier transformed infrared spectroscopy, contact angle, roughness, and scanning electron microscopy. Results revealed that PHBV/GNS nanocomposites can be totally degraded in the presence of Penicillium funiculosum; however, it will be necessary high incubation period. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44234.     

Incorporation of benzothiadiazole moiety at junction of polyfluorene–polytriarylamime block copolymer for effective color tuning in organic light emitting diode

Block copolymer consisting of polyfluorene and polytriarylamine with benzothiadiazole moiety at the junction is prepared in order to obtain an orange emitting polymer via Suzuki‐Miyaura followed by Buchwald‐Hartwig coupling reactions. Electroluminescent device fabricated with resulting block copolymer exhibit only orange emission, although slight blue emission is observed in the fluorescent spectrum for the thin film, indicating that benzothiadiazole part plays a role of an effective trap site. Devices based on polyfluorene homopolymer doped with block copolymer (10 wt %) or an orange emitting model compound at the corresponding content of benzotiadiazole unit are also fabricated. The device with the model compound exhibits orange emission with Commission Internationale de l'Éclairage (CIE) coordinate of (0.58, 0.42), whereas that with block copolymer pale orange with the coordinate of (0.44, 0.38). This fact is probably due to the preferential distribution of block copolymer at the vicinity of anode via hydrophilic interaction of trioxyethylene side chains with poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45393.     

Improved quantum efficiency of Sr(Al,Si)5(O,N)7:Ce3+ by selection of Ce raw material

The luminescence properties of yellow-emitting Ce³⁺-doped Sr-containing sialon phosphor Sr(Al,Si)₅(O,N)₇:Ce³⁺ were notably improved by the Ce raw material selection. By changing the Ce raw material from oxides to nitrides or chlorides, the emission wavelength shifted to above 560 nm, which is beneficial for higher color rendering index white light-emitting diodes. This result from an increase in the covalency of the host crystal being associated with a decrease in the oxygen content. When Ce chloride was used, both the absorption and internal quantum efficiency increased, resulting in an increase in the external quantum efficiency up to 65%–72%. Inductively coupled plasma mass spectrometry, X-ray diffraction, and electron spin resonance measurements showed that the reason for the absorption increase is an increase in Ce³⁺ content and suppression of the generation of the second phase, and the reason for the increase in the internal quantum efficiency is a decrease in the host crystal absorption via suppression of anion vacancy generation. It was found that Ce chloride not only suppresses oxygen impurities but also acts as a flux that results in improved crystallinity.     

Biased distribution of the branched-chain fatty acids in ceramides of vernix caseosa

The compositions of ester- and amide-linked fatty acids from ceramides of human vernix caseosa were described with emphasis on the distribution of the branched-chain fatty acid (BCFA). Two novel ceramides were isolated from vernix caseosa in the course of this study: the acylated type of esterified α-OH-hydroxyacid/sphingosine ceramide (Cer[EAS]) and nonacylated type of non-OH fatty acid/hydroxysphingosine ceramide (Cer[NH]). Their chemical structures were identified by nuclear magnetic resonance and chemical procedure. The Cer[EAS] was an acylceramide and consisted of the highest concentrations of ester- and amide-linked BCFA (62 and 67%, respectively). The iso- or anteiso-branching structures of the aliphatic chains were confirmed by the mass spectra of their picolinyl or pyrrolidide derivatives. As a whole, amide-linked fatty acids of ceramides 1–7 and Cer[NH] were normal types of straight-chain fatty acids with or without α- or ω-hydroxylation. The BCFA concentrations of amide-linked fatty acids in these ceramides (ceramides 1–7 and Cer[NH]) were low and less than 10%. The BCFA thus occurred exclusively in a novel acylceramide of Cer[EAS] in the vernix caseosa.     

Fracture Energy of an Aligned Porous Silicon Nitride

The fracture energy of a porous silicon nitride with aligned fibrous grains was investigated, using a chevron-notched-beam technique. A crack was constrained to propagate normal to the grain alignment. The obtained fracture energy was ∼500 J/m², which was ∼7 times larger than that of a dense silicon nitride with randomly oriented fibrous grains. The large fracture energy was attributable primarily to the sliding resistance associated with interlocking grains.     

Characterization and Sintering Behavior of Alkoxide-Derived Aluminosilicate Powders

Submicrometer SiO₂-Al₂O₃ powders with compositions of 46.5 to 76.6 wt% Al₂O₃ were prepared by hydrolysis of mixed alkoxides. Phase change, mullite composition, and particle size of powders with heating were analyzed by DTA, XRD, IR, BET, and TEM. As-produced amorphous powders partially transformed to mullite and Al-Si spinel at around 980°C. The compositions of mullite produced at 1400° and 1550°C were richer in Al₂O₃ than the compositions of stable mullite solid solutions predicted from the phase diagram of the SiO₂-Al₂O₃ system. Particle size decreased with increasing Al₂O₃ content. The sintered densities depended upon the amount of SiO₂-rich glassy phase formed during sintering and the green density expressed as a function of particle size.     

CO gas sensor devices plasma-polymerized from tetramethyltin

Thin films plasma-polymerized from tetramethyltin was applied for CO gas sensor device. The films formed from tetramethyltin contains alkyl chains with organic tin moieties, and pyrolysis of them at 350–500°C yields carbonized films with SnO₂ moieties. The electrical resistance for the films pyrolized at 350–500°C decreases in exposing to CO gas. The sensitivity, the ratio of the electrical resistance between in air and in CO atmosphere, is enhanced by catalytic actions of palladium chloride, specially in operation at low temperatures below 50°C. The gas sensitivity between CO and other gases such as ethanol, methane, and propane gases is good. The possible determination of CO gas concentration by the sensor device is in ranges from 10 to 1000 ppm.     

Further Investigations on the Promoting Effect of Mesoporous Silica on Base-Catalyzed Aldol Reaction

Addition of an ordered mesoporous silica to a mixture of an aldol reaction, comprising 4-nitrobenzaldehyde with acetone catalyzed by organic amines, caused significant increase in the reaction rate to afford the β-hydroxyketone in high yield. A cooperative effect between the surface silanol and amine was considered to be the likely reason for the rate-enhancement, which was supported by FTIR spectroscopy.     

Improvement of impact toughness of 5Mn-1Al-0.5Ti steel by intercritical annealing

The present study is aimed at improving the impact toughness of 5Mn-1Al-0.5Ti steel by incorporating ferrite-martensite dual phase microstructure by intercritical annealing. Although (8-12)Mn martensitic steels usually show very low impact toughness due to the occurrence of intergranular fracture, the martensitic structure of the present 5Mn-1Al-0.5Ti steel fails by transgranular cleavage fracture due to higher grain boundary strength than matrix strength incurred by reduced Mn content and segregation of Ti along grain boundaries. Nevertheless, it still shows very poor impact toughness at room temperature due to its coarse grain size. The application of intercritical annealing, i.e., formation of dual phase microstructure, is shown to significantly decrease ductile-to-brittle transition temperature (DBTT), with only a small degradation of tensile properties; however, microstructural examinations show that most of ferrite/martensite interfaces have a character of low angle boundaries and therefore such decrease in DBTT is not necessarily due to the formation of ferrite-martensite dual phase structure, but rather to the refinement of grain size by low temperature annealing.     

Effect of Gallia Addition on the Sintering Behavior of Samaria-Doped Ceria

Samaria-doped ceria (SDC) was prepared by using the solid-state reaction method. Sintering of SDC was significantly promoted by adding a small amount of gallium. SDC that had 1% of gallium added, sintered at 1450°C, showed almost the same properties as SDC sintered at 1600°C. Measurements showed that the addition of gallia could reduce the sintering temperature by 150°C without deteriorating the properties of SDC as an electrolyte for solid oxide fuel cells.