1-Chloro-1,3-butadiene copolymers. I. Synthesis of copolymer with 1,3-butadiene and physical properties of its vulcanizate

Emulsion copolymerization of 1-chloro-1,3-butadiene and 1,3-butadiene was carried out using potassium persulfate at 50°C. The thus synthesized 1-chloro-1,3-butadiene copolymer was possible to be cured with 2-mercaptoimidazoline (MI) as well as with sulfur. The tensile strength of the MI vulcanizate of the copolymer compounded with 30 phr HAF black reached 100 kg/cm² and was higher than that of the sulfur vulcanizate. Moreover, these two vulcanizates showed higher tensile strengths than the sulfur vulcanizate of emulsion butadiene rubber. The addition of the copolymer to the blend of chloroprene rubber (Neoprene GRT) and butadiene rubber extremely improved the elongation and the tensile strength. Dynamic measurements of the vulcanizates showed that the glass transition temperature of the copolymer was situated at the region between that of butadiene rubber and that of chloroprene rubber.     

Swelling of hydrophilic polymers. II

The swelling of five types of Sephadex that are either nonionic (G) or possess one of four different ionic groups [sodium carboxymethyl (CM), sodium sulfopropyl (SP), diethyl-aminoethyl chloride (DEAE), diethyl - (2-hydroxypropyl) aminoethyl chloride (QAE)] in the same skeleton of the molecule has been studied by picture analysis and by calorimetry. Inducing dissociation of the ionic group in the polymer skeleton increased the water swelling. By the addition of sodium chloride, the maximum swelling volume of nonionic Sephadex was only slightly decreased. However, that of ionic polymers was considerably decreased. The variation of the apparent first-order rate constant of the swelling and that of the maximum swelling volume show the same tendency. The maximum heats of swelling were 93.2 ± 7.1 J g^?1 for G, 128.8 ± 9.1 J g^?1 for CM, 92.3 ± 8.0 J g^?1 for SP, 68.8 ± 10.5 J g^?1 for DEAE, and 67.0 ± 7.2 J g^?1 for QAE and did not depend on the concentration of sodium chloride. From the results obtained, we conclude that the nonionic Sephadex swells only by hydration but that ionic Sephadexes swell mainly by the osmotic pressure due to the counterions of the ionic groups and that the swelling ratio is not dependent on the kinds of ions but on the ionic concentration. Most of the water in the gels of ionic Sephadexes is free water that does not interact with the Sephadexes. © 1993 John Wiley & Sons, Inc.     

Nonlinear vibration induced by the water-film whirl and whip in a sliding bearing rotor system

Many industrial applications and experiments have shown that sliding bearings often experience fluid film whip due to nonlinear fluid film forces which can cause rotor-stator rub-impact failures. The oil-film whips have attracted many studies while the water-film whips in the water lubricated sliding bearing have been little researched with the mechanism still an open problem. The dynamic fluid film forces in a water sliding bearing are investigated numerically with rotational, whirling and squeezing motions of the journal using a nonlinear model to identify the relationships between the three motions. Rotor speed-up and slow-down experiments are then conducted with the rotor system supported by a water lubricated sliding bearing to induce the water-film whirl/whip and verify the relationship. The experimental results show that the vibrations of the journal alternated between increasing and decreasing rather than continuously increasing as the rotational speed increased to twice the first critical speed, which can be explained well by the nonlinear model. The radial growth rate of the whirl motion greatly affects the whirl frequency of the journal and is responsible for the frequency lock in the water-film whip. Further analysis shows that increasing the lubricating water flow rate changes the water-film whirl/whip characteristics, reduces the first critical speed, advances the time when significant water-film whirling motion occurs, and also increases the vibration amplitude at the bearing center which may lead to the rotor-stator rub-impact. The study gives the insight into the water-film whirl and whip in the water lubricated sliding bearing.     

High-pressure Study of a Doped-type Organic Superconductor, κ-(BEDT-TTF)4Hg2.89Br8

Physical properties of the organic charge-transfer complex that may be regarded as a doping system are presented. We measured resistivity of an ambient-pressure superconductor, κ-(BEDT-TTF)₄Hg_2.89Br₈, as functions of temperature, magnetic field, and pressure. Metallic and superconducting states of this salt are possibly attributable to the doping effect, which originates from incommensurability of Hg chain because band structure calculation predicts strong electron-electron correlation enough to localize the itinerant electrons. We uncovered anomalous pressure and magnetic field dependences of superconductivity as well as non-Fermi liquid behavior in the normal-state resistivity at low pressures. In addition, we observed a pressure-induced crossover to the Fermi liquid behavior, which is seen in non-doped κ-type salts at any pressures.     

Development of enzyme-linked immunosorbent assay for detection of alkylphenol polyethoxylates and their biodegradation products

An enzyme-linked immunosorbent assay (ELISA) was developed for the quantitative analysis of alkylphenol polyethoxylates (APnEOs) and their biodegradation products. To generate a specific monoclonal antibody (mAb) for the ELISA, hybridoma cells were produced by the fusion of mouse myeloma cells and spleen cells from mice immunized with nonylphenol polyethoxylate (NPnEO) derivatives coupled to bovine serum albumin. The developed ELISA showed the detection limits of 16 and 30 μg/L NP10EO when 10% and 60% (v/v) methanol solutions were used as assay diluent. The mAb was shown to be specific to APnEOs and their metabolites, such as short-ethoxy-chain APnEOs and alkylphenoxy carboxylic acids, except for nonylphenol. Moreover, no response was observed with non-APnEO surfactants as well as other compounds structurally similar to APnEOs. The percentage river water recoveries of 85–118% were obtained for 10 μg/L NP10EO fortification after preconcentration by C18 solid-phase extraction. The ELISA was also validated by comparing it with high-performance liquid chromatography for the analysis of APnEOs and their metabolites in river samples; the correlation coefficient between the values obtained by these assays was 0.96.     

Application of deaerated water in swelling of cellulose and amylose and cotton desizing with enzyme

The effect of deaerated water on the swelling of cellulose and amylose and on the application in cotton desizing with enzyme that contains necessarily these swelling processes were studied. The total volume changes of the swelling of cellulose and amylose were measured by dilatometry. The total volume changes of cellulose and amylose were more negative in deaerated water. In deaerated water, the total volume changes are 142 ± 6% for cellulose and 229 ± 2% for amylose to those in air‐present water. The rates of cotton desizing with two kinds of enzymes were studied by measuring the concentration of generated sugars by using HPLC. Higher efficiency of 140–150% was obtained in deaerated water than in water containing dissolved gases of air, oxygen, or nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1693–1700, 1999     

Fracture toughness evaluation for multidirectional CFRP by the Raman coating method

The Mode I fracture toughness for multidirectional carbon-fiber-reinforced plastics (CFRP) was investigated by using double-cantilever beam (DCB) specimens with Raman spectroscopy. A thin PbO film was deposited on the specimen surface by physical vapor deposition (PVD) as the pretreatment for strain measurement, and then the fracture toughness was determined from the results of Raman spectroscopy measurement. These results agreed with the results by conventional experimental methods and numerical analyses. The fracture surfaces of DCB specimens were observed by scanning electron microscope (SEM); the fracture surfaces differed because of different critical energy release rates.     

Time of exposure to lubricating liquid for predicting wear of UHMWPE in joint prostheses

It is generally agreed that contact pressure and sliding speed are the predominant factors for the prediction of wear of ultrahigh‐molecular‐weight polyethylene (UHMWPE) in joint prostheses. A new parameter for predicting the wear of UHMWPE has been introduced with a wear test in vitro. The parameter is the time of exposure to a lubricating liquid on a bearing surface. A pin‐on‐disc machine was designed such that the exposure time of a Co Cr Mo alloy disc to a lubricating liquid could be varied. The specific wear of UHMWPE was increased by a decrease in the exposure time, even if the contact pressure and the sliding speed were held constant. The parameter is able to account for the contact pressure set in the experiment (2.0–20.0 mPa), and clarifies the conditions under which the specific wear of UHMWPE is found to be high.     

Fracture toughness and impact strength of anhydride‐cured biobased epoxy

Biobased neat epoxy materials containing functionalized vegetable oils (FVO), such as epoxidized linseed oil (ELO) and epoxidized soybean oil (ESO), were processed with an anhydride curing agent. A percentage of diglycidyl ether of bisphenol F (DGEBF) was replaced by ELO or ESO. The selection of the DGEBF, FVO, and an anhydride‐curing agent resulted in an excellent combination to produce a new biobased epoxy material having a high elastic modulus and high glass transition temperature. Izod impact strength and fracture toughness were significantly improved dependent on FVO content, which produced a phase‐separated morphology. POLYM. ENG. SCI., 45:487–495, 2005. © 2005 Society of Plastics Engineers     

Involvement of Molecular Mechanisms between T/B Cells and IL-23: From Palmoplantar Pustulosis to Autoimmune Diseases

Palmoplantar pustulosis (PPP) is a disease that causes recurrent blisters and aseptic pustules on the palms and soles. It has been suggested that both innate and acquired immunity are involved. In particular, based on the tonsils and basic experiments, it has been assumed that T and B cells are involved in its pathogenesis. In addition, the results of clinical trials have suggested that IL-23 is closely related to the pathogenesis. This review describes PPP and the genetic background, the factors involved in the onset and exacerbation of disease and its relation to the molecular mechanism. In addition, we describe the usefulness of biological therapy and its implications in relation to the importance in pathology, the pathogenesis of PPP, the importance of the role of the IL-23–Th17 axis and IL-36 in PPP. Furthermore, we describe an animal experimental model of PPP, the efficacy and mechanism of action of guselkumab, an anti-IL-23 antibody, the latest research, and finally the possibility for it to be effective for other autoimmune diseases.