Polymer gel electrolytes prepared from P(EG‐co‐PG) and their nanocomposites using organically modified montmorillonite

Polymer gel electrolytes were prepared by thermal crosslinking reaction of a series of acrylic end‐capped poly(ethylene glycol) and poly(propylene glycol) [P(EG‐co‐PG)] having various geometries and molecular weights. Acrylic end‐capped prepolymers were prepared by the esterification of low molecular weight (M_n: 1900–5000) P(EG‐co‐PG) with acrylic acid. The linear increase in the ionic conductivity of polymer gel electrolyte films was observed with increasing temperature. The increase in the conductivity was also monitored by increasing the molecular weight of precursor polymer. Nanocomposite electrolytes were prepared by the addition of 5 wt % of organically modified layered silicate (montmorillonite) into the gel polymer electrolytes. The enhancement of the ionic conductivity as well as mechanical properties was observed in the nanocomposite systems. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 894–899, 2004     

Computational fluid dynamics (CFD) analysis and experimental study for toxic hazardous waste destruction in the cavity incinerator

We undertook numerical and experimental studies to develop a better incineration method for the destruction of CC1₄. A phenomenological model for the turbulent reaction of CC1₄, including a flame inhibition feature, has been successfully incorporated into a commercial code, simulating the incineration processes of this compound. The gaseous flow solution was obtained using SIMPLEST, a derivative of Patankar’s SIMPLE algorithm, with a k-ε turbulence model. A modified fast chemistry turbulent reaction model was developed to describe the flame inhibition due to the presence of CC1₄, considering the corresponding burning velocity data of these mixtures. An experiment was carried out on a 5.2 kW laboratory scale, transportable, cavity-type incinerator, which warrants a sufficient residence time and effective turbulent mixing by the formation of a strong recirculation region in a combustor. To this end, the specific configuration of the incinerator was manufactured to consist of two opposing jets and a rearward facing step. The calculated data were in close agreement with the experimental data for the concentrations of major species, such as CCI₄ and HCl, together with the temperature profiles. The experimental test gave the desired DRE of above 99.99%.     

The influence of filler on the emission properties and rheology of carbon nanotube paste

CNT paste consists of organic solution, inorganic binder and filler. Organic solution contains organic resins and solvent including surfactants which finely disperse CNTs. Filler affects surface morphology, electron emission property, viscosity, and rheological characteristics of CNT paste. We used different fillers such as silver and alumina in CNT paste for special function. The emission properties of CNT paste with silver are similar to those of CNT paste with alumina if filler portion is the same. From the scanning electron microscope (SEM) different morphologies of CNTs was observed depending on the type of filler. CNT paste which showed good emission property had vertically well-aligned CNTs on the surface after surface treatment using adhesive tape. We measured viscosity and rheological properties with rheometer RS600 from HAAKE. Emission property of CNT paste was evaluated in vacuum chamber of 10^{− 6} Torr with pulse generator and duty was 1/500.     

Methane generation from Miocene lacustrine coals and organic-rich sedimentary rocks containing different types of organic matter

Ten selected samples with varying types and amounts of organic matter from two Miocene lacustrine basins in northwestern Turkey were analyzed by programmed-temperature open-system pyrolysis to determine methane generation potential and reaction kinetics. Open-system pyrolysis was performed at heating rates 0.1, 0.7 and 5.0 K/min, where generated gases were measured using an on-line gas chromatograph. Frequency factors and activation energy distributions of reaction kinetics for methane generation from the investigated lacustrine coals and sedimentary rocks indicated that type of kerogen controls the sequential order of methane generation. Methane from Type-III kerogen is generated at lower temperatures, which will be followed by methane from Type-II and Type-I kerogen. Methane generation potentials in the range 14-35 mg CH₄/g TOC correlates also with type of organic matter. For Type-III kerogen up to 28% of the total hydrocarbon generation potential belongs to methane. The respective value is only 2% for a Type-I kerogen.     

Durable antimicrobial treatment of cotton fabrics using N‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride and polycarboxylic acids

N‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride (HTCC), a water‐soluble chitosan quaternary ammonium derivative, was used as an antimicrobial agent for cotton fabrics. HTCC has a lower minimum inhibition concentration (MIC) against Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli compared to that of chitosan; however, the imparted antimicrobial activity is lost on laundering. Thus crosslinking agents were utilized to obtain a durable antimicrobial treatment by immobilizing HTCC. Several crosslinkers such as dimethyloldihydroxyethylene urea (DMDHEU), butanetetracarboxylic acid (BTCA), and citric acid (CA) were used with HTCC to improve the laundering durability of HTCC treatment by covalent bond formation between the crosslinker, HTCC and cellulose. The polycarboxylic acid treatment was superior to the DMDHEU treatment in terms of prolonged antimicrobial activity of the treated cotton after successive laundering. Also, the cotton treated with HTCC and BTCA showed improved durable press properties without excessive deterioration in mechanical strength or whiteness when compared to the citric acid treatment. With the addition of only 0.1% HTCC to BTCA solutions, the treated fabrics showed durable antimicrobial activity up to 20 laundering cycles. The wrinkle recovery angle and strength retention of the treated fabrics were not adversely affected with the addition of HTCC. Therefore, BTCA can be used with HTCC in one bath to impart durability of antimicrobial activity along with durable press properties to cotton fabric. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1567–1572, 2003     

Continuous ethanol production from wood hydrolysate by chemostat and total cell retention culture

Chemostat and total cell retention cultures with internal filter system ofSaecharomyc.es cerevisiae H1-7 were carried out to produce ethanol from wood hydrolysate. Maximum ethanol productivity obtained in a chemostat with the aeration rate of 1 vvm was 3.79 g/(L·h). This was 20% higher than that in a chemostat without aeration. However, the substrate was not completely consumed at the dilution rate with the maximum productivity. The realistic productivity, which has higher than 99% conversion rate of substrate, was. 2.95 g/(L·h). The maximum productivity in the total cell retention culture was 6.65 g/(L·h) at the dilution rate of 0.19 h¹ and the residual glucose concentration was negligible.     

Interfacial adhesion reaction of polyethylene and starch blends using maleated polyethylene reactive compatibilizer

The interfacial reaction of the polyethylene (PE)/starch blend system containing the reactive compatibilizer maleated polyethylene (m‐PE) was directly characterized by Fourier transform infrared (FTIR) spectroscopy. A significant amount of anhydride groups on m‐PE existed as hydrolyzed forms, resulting in a large amount of carboxyl groups. Using a vacuum‐heating‐cell designed in the laboratory, the carboxyl groups were successfully transformed into the dehydrolyzed state (i.e., anhydride group). This result enabled the direct spectroscopic observation of chemical reaction occurring at the interface. For the PE/starch blend system containing m‐PE, the chemical reaction at the interface was verified by the evolution of ester and carboxyl groups in the FTIR spectra. The effect of the reactive compatibilizer on the interfacial morphology was also examined by scanning electron micrography (SEM). Enhanced interfacial adhesion was clearly observed for the blend system containing reactive compatibilizer. Tensile strengths of blend systems containing m‐PE also increased noticeably compared with the corresponding system without compatibilizer. A similar observation was made for the breaking elongation data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 767–776, 2002     

Comparison of liquid-phase and methanol-swelling crosslinking processes of polyimide dense membrane for CO2/CH4 separation

To overcome the plasticization effect in polyimide membranes, many researchers have proposed crosslinking method. This can reduce an inter-segmental mobility by tightening and rigidifying the polymer chains. However, it is difficult to modify the whole polymer chains throughout the membrane because the reaction can be hindered by the diffusion rate of the crosslinker. In particular, it is hard for bulky crosslinker to penetrate a dense membrane with a small d-spacing. This study investigated the effect of crosslinking a dense Matrimid membrane with p-phenylenediamine (p-PDA) via two different crosslinking methods (i.e., methanol-swelling crosslinking process [M-SCP] and liquid-phase crosslinking process [L-PCP]). Most of the crosslinking reaction in M-SCP occurs on the membrane surface due to difficulty in penetration of the bulky p-PDA into the Matrimid dense membrane. In contrast, the L-PCP allows uniform crosslinking across the membrane. The membranes crosslinked using L-PCP showed excellent chemical resistance. Furthermore, the plasticization phenomenon was not observed in the membranes crosslinked using L-PCP with p-PDA more than 15%. Meanwhile, the membrane crosslinked using M-SCP exhibited poor plasticization and chemical resistance properties. These results showed that the L-PCP method can be more effective for the crosslinking of dense membrane to deliver both high plasticization and chemical resistance.     

Prediction model for surface temperature of roller and densification of iron powder during hot roll pressing

The hot roll pressing of iron powder with several rotating speeds was carried out on a pilot-plant scale. From these experiments, it was confirmed that the surface temperature of roller was increased with increasing its rotating speed. It was also known that the heat transfer coefficient between the iron powder and the roller surface is closely related with the rotating speed of roller. These results were quantitatively described by using a mathematical model which was derived based on the steady-state heat transfer during hot roll pressing. In addition, the densification behavior of iron powder during the hot roll pressing was simulated by a finite element model based on the arbitrary Lagrangian and Eulerian (ALE) method and a yield criterion for metal powder. From these models, the maximum critical rotating speed of roller during the hot roll pressing, in which the roller could hold out against the thermal fracture, could be determined.     

The form error prediction in side wall machining considering tool deflection

In this research, an effective method for the form error prediction in side wall machining with a flat end mill is suggested. The form error is predicted directly from the tool deflection without surface generation by cutting edge locus with time simulation. The developed model can predict the surface form error accurately about 300 times faster than the previous method. Cutting forces and tool deflection are calculated considering tool geometry, tool setting error and machine tool stiffness. The characteristics and the difference of generated surface shape in up milling and down milling are discussed. The usefulness of the presented method is verified from a set of experiments under various cutting conditions generally used in die and mold manufacturing. This study contributes to real time surface shape estimation and cutting process planning for the improvement of form accuracy.