Elucidation of Softening Mechanism in Rinse Cycle Fabric Softeners. Part 1: Effect of Hydrogen Bonding

Most softening agents, such as rinse cycle fabric softeners, used by consumers at home contain cationic surfactants that have two long alkyl chains as their main component. The softening mechanism on fibers, especially cotton, has not yet been scientifically established, despite the market prevalence of fabric softeners for decades. One explanation for the softening effect is that the friction between fibers is reduced. According to this explanation, the fiber surfaces are coated by layers of alkyl chains. Because of the low coefficient of friction between alkyl chain layers of low surface energy, the fibers easily slide against one another yielding softer cotton clothing. However, no direct scientific evidence exists to prove the validity of this explanation. The softening mechanism of cotton yarn is discussed in this paper. Bending force values of cotton yarn treated with several concentrations of softener are measured by bend testing, and cotton and polyester yarns are compared. Results indicate that increases in cotton yarn hardness after natural drying are caused by cross‐linking among inner fibers aided by bound water. This type of bound water has been known to exist even after 2 days of drying at 25 °C and 60 % relative humidity. Yarn dried in vacuo is soft, similar to that treated with softener. Thus, some of the softening effect caused by fabric softeners on cotton can be attributed to the prevention of cross‐linking by bound water between cotton fibers.     

Lessons from Mouse Models of High-Fat Diet-Induced NAFLD

Nonalcoholic fatty liver disease (NAFLD) encompasses a clinicopathologic spectrum of diseases ranging from isolated hepatic steatosis to nonalcoholic steatohepatitis (NASH), the more aggressive form of fatty liver disease that may progress to cirrhosis and cirrhosis-related complications, including hepatocellular carcinoma. The prevalence of NAFLD, including NASH, is also increasing in parallel with the growing epidemics of obesity and diabetes. However, the causal relationships between obesity and/or diabetes and NASH or liver tumorigenesis have not yet been clearly elucidated. Animal models of NAFLD/NASH provide crucial information, not only for elucidating the pathogenesis of NAFLD/NASH, but also for examining therapeutic effects of various agents. A high-fat diet is widely used to produce hepatic steatosis and NASH in experimental animals. Several studies, including our own, have shown that long-term high-fat diet loading, which can induce obesity and insulin resistance, can also induce NASH and liver tumorigenesis in C57BL/6J mice. In this article, we discuss the pathophysiology of and treatment strategies for NAFLD and subsequent NAFLD-related complications such as NASH and liver tumorigenesis, mainly based on lessons learned from mouse models of high-fat diet-induced NAFLD/NASH.     

Adhesion properties of polyurethane pressure-sensitive adhesive

In this study, the adhesion properties of polyurethane (PUR) pressure-sensitive adhesive (PSA) were investigated. The PUR-PSA was prepared by the cross-linking reaction of a urethane polymer consisting of toluene-2,4-diisocyanate and poly(propylene glycol) components using polyisocyanate as a cross-linking agent. The peel strength increased with the cross-linking agent content and exhibited cohesive failure until the maximum value, after which it decreased with interfacial failure. The PUR-PSA exhibited frequency dependence of the storage modulus obtained from dynamic viscoelastic measurements, but did not show dependence of the tack on the rolling rate measured using a rolling cylinder tack test under the experimental conditions used, which is quite different from the acrylic block copolymer/tackifier system. The PUR-PSA showed strong contact time dependence of tack measured by a probe tack test. The tendency was significantly larger than for the acrylic block copolymer/tackifier system. Therefore, the storage modulus increased, whereas the interfacial adhesion seems to be decreased with increase in the rolling rate for this PUR-PSA system. It was estimated that the influence of rolling rate on the interfacial adhesion and the storage modulus was offset, and, as a result, the rolling cylinder tack did not exhibit rate dependency.     

Characterization and gas‐permeation properties of crosslinked diacetylene‐containing polymer membranes from ferulic acid

Thermally and UV crosslinked poly[propargyl(3‐methoxy‐4‐propargyloxy) cinnamate] (PPOF) were investigated in terms of their physical, thermal, optical, and gas‐permeation properties. The crosslinked membranes had high gel contents because of the formation of a diacetylene network. The wide‐angle X‐ray diffraction patterns showed that all of the membranes were amorphous in structure, regardless of the type of crosslinking reaction. The membrane density increased after the crosslinking reaction; this suggested that the free volume of the crosslinked membrane was lower than that of the untreated membranes. Drastic color changes in the membranes were also observed because of the highly conjugated crosslinked network of diacetylene. In addition, the conjugation caused by diacetylene crosslinking led to visible absorption within the range 400–600 nm. The gas permeation of the crosslinked membrane was reduced compared with that of the untreated membranes. In particular, the gas permeability of the thermally crosslinked membrane was lower than that of UV‐irradiated membrane. On the basis of this result, the degree of crosslinking by thermal treatment was higher than that of UV irradiation. Hence, the crosslinked PPOF membranes showed improved gas‐barrier properties due to the high conjugation of the crosslinked diacetylene network induced by thermal treatment and UV irradiation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Support Effects of Carbon on Pt Catalysts

Experimental evidence for support effect of carbon are summarized for Pt or PtRu catalysts supported by carbon nanotubes and graphene as well as for model catalysts of Pt/HOPG (highly oriented pyrolytic graphite). The electronic modification of Pt catalysts by the support effect is explained by a π–d interaction at the interface between graphitic surface and Pt. The interface interaction is related to non-bonding localized states of carbon, which are observed by scanning tunneling spectroscopy near defects or the doped-nitrogen atom on HOPG. The localized states propagate to a few nanometer regions behaving as acid and basic sites.     

Multiangle Polarimetry of Thermal Emission and Light Scattering by Individual Particles in Airflow

The generalized Kirchhoff's law predicts that the polarization state of thermal emission from an individual small particle depends on the particle shape. We show for the first time experimental evidence confirming this prediction for particles smaller than the wavelength by using a newly developed laser-induced incandescence instrument and a theoretical model that can predict the signals of thermal emission and light scattering for an ellipsoid under the dipole approximation (Rayleigh ellipsoid). We use single-sphere (singlet) and two-sphere clusters (doublet) of polystyrene latex spheres as primary test particles. These are currently available, well-characterized spherical and nonspherical particles, respectively. The polarization states of thermal emission and scattered light of graphite particles smaller than the wavelength show a good agreement with model calculations for plate-like Rayleigh-spheroids, consistent with their plate-like shapes observed by a transmission electron microscope. We propose that the measurement of the polarization state of thermal emission may be applicable to real-time analysis of the shape of light-absorbing particles in air.     

Evaluation of a New Particle Trap in a Laser Desorption Mass Spectrometer for Online Measurement of Aerosol Composition

We have developed a new analyzer for the online measurement of aerosol composition: a particle trap laser desorption mass spectrometer (PT-LDMS). The main components of the instrument include an aerodynamic lens, a particle trap enclosed by a quartz cell, a quadrupole mass spectrometer (QMS), a vacuum chamber incorporating the above components, and a carbon dioxide (CO₂) laser (wavelength 10.6 μm). The aerodynamic lens generates a beam of submicron particles, which is focused on a small area on the particle trap. The particle trap consists of custom-made mesh layers, the structure of which was newly designed using engineering techniques for micro electro mechanical systems (MEMS). A large number of mesh frames are well arranged in the trap, and particles can be efficiently captured after multiple impactions on the frames. The CO₂ laser is used to vaporize aerosol compounds captured on the particle trap. The evolved gas confined within the quartz cell is analyzed using an electron impact ionization (EI) QMS to quantify the chemical composition of the particles. The concept of the PT-LDMS and first evaluation of its performance are presented, specifically focusing on the structure and performance of the particle trap.     

Zr(IV)?Fe(III), ?Ga(III), and ?Sn(IV) Binary Metal Complexes as Synergistic and Reusable Esterification Catalysts

Synergism in catalytic activity with the combined use of Hf(O‐i‐Pr)₄ or Zr(O‐i‐Pr)₄ and Fe(O‐i‐Pr)₃ for direct esterification and a very simple method for their extraction with ionic liquids for their recovery and reuse are described. This Zr(IV) Fe(III) complex is an environmentally benign catalyst due to its high turnover number, extremely mild Lewis acidity, low toxicity, reusability, and commercial availability at low cost.     

Determination of Thermal Spray Coating Property with Curvature Measurements

Real-time curvature measurement of a coating-substrate system during deposition has facilitated the monitoring of coating stresses and provided additional insights into thermal spray deposition mechanisms. However, the non-equilibrium state of coating formation along with harsh spray booth environment introduces complexity not only in data interpretation but also in the coating properties estimation. In this paper, a new procedure is proposed to estimate the elastic modulus of thermal sprayed ceramic coatings using in situ curvature and temperature measurements. In order to correlate the measurable parameters to coating elastic modulus, a systematic study is conducted to develop a suitable methodology. First, various finite element model analyses are carried out to formulate suitable relations between the measurements and elastic modulus. Subsequently, experiments are conducted to validate the procedure to estimate coating moduli. The results are compared with more accurate measurements obtained from post-deposition characterization technique under low temperature thermal cycles. The comparison suggests that the moduli estimated using the proposed procedure are in good agreements with those obtained from the post-deposition technique. Further, the nonlinear response of coatings are evaluated from the estimated moduli during deposition and cool down, which offer additional information on the characteristics of thermal spray coatings.     

Tribological properties of polymer composites with diamond-like carbon flakes

Composites of epoxy resin with diamond-like carbon (DLC) flakes were fabricated. The DLC flakes were prepared from a DLC film deposited by chemical vapor deposition on an aluminum substrate. The tribological properties of composites were evaluated in air and water environments using a reciprocating friction tester and an AISI 440C mating ball. The friction coefficient of the epoxy composite decreased from 0.90 to 0.69 in air and from 0.71 to 0.29 in water with the addition of DLC flakes. The specific wear rate of the composite also decreased from 5 × 10^? 5 to 7 × 10^? 6 mm³/N m in air and from 4 × 10^? 5 to 4 × 10^? 6 mm³/N m in water. In contrast, the wear of the mating ball increased. Furthermore, the tribological properties of DLC flakes as an additive in water were evaluated. The suspension of powdered DLC in water reduced the friction coefficient of epoxy resin against the AISI 440C mating ball. Furthermore, the wear of the resin was negligibly small, although severe abrasive wear on the mating ball was observed.