Compatibility analysis of Nylon 6 and poly(ethylene-n-butyl acrylate-maleic anhydride) elastomer blends using isothermal crystallization kinetics

Nylon 6 is a widely used engineering polymer, and has relatively poor impact strength. Ethylene, n-Butyl acrylate, maleic anhydride (E-nBA-MAH) terpolymer is blended with Nylon 6 to enhance its impact strength. Mixture should be compatible to be used in applications. The bare interaction energy between Nylon 6 and E-nBA-MAH terpolymer is calculated according to melting point depression approach using both Flory–Huggins (FH) Theory and Sanchez–Lacombe Equation of State (SL EOS). It demonstrates that blends are thermodynamically favorable to any arrangements. Yet, isothermal crystallization kinetics and WAXS crystallization peaks of blends reveal that mixtures of various compositions have different crystallization behaviors and require alternating crystallization energy due to crystalline structures of individual polymers. Also, SEM images support that after 5% addition of elastomeric terpolymer, interaction loosens due to strong crystalline structure of Nylon 6.     

Mechanical,Structural and Thermal Properties of Transparent Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>–Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–ZnO–TeO<Subscript>2</Subscript> Glass System

Oxide based optical glass materials has important potential material in many applications from fiber optic to sensor due to the high transparency and amourphous structures. The objective of this study is to synthesize the novel optical glass materials based on the bismuth and aluminum contents to be able to determine the physical, chemical and mechanical properties by considering the systematic experimental steps. In this study, Bi₂O₃–Al₂O₃ based tellurite optical glasses have been prepared by using conventional melt quenching method as a function of the both Bi₂O₃ and Al₂O₃ compositions. There is a strong interactions between the glass former and modifier ions that might effect on the structure and mechanical properties. During the experimental steps, thermal, structural and mechanical properties of the prepared glass materials have been determined considering the DTA/DSC, FT-IR spectroscopy, SEM and Vicker’s hardness techniques, respectively. Thermal parameters, like glass transition, T_g, onset, T_x, crystallization, T_p, and melting, T_m, temperatures were obtained by using DTA scan.     

The effect of glucose oxidase enzyme on wool fibres

Glucose oxidase is a type of enzyme that converts glucose into hydrogen peroxide and gluconic acid by enzymatic reaction. Glucose oxidase is widely used in industry; however, in the textile industry, glucose oxidase has only received academic interest. Previously, wool was bleached by some reducing agents; however, currently in industry, hydrogen peroxide dominates the bleaching of wool fibres. In this study, the effect of glucose oxidase enzyme treatment on wool merino fibres and dyeability properties was investigated. Wool fibres were treated with glucose oxidase enzyme, after which the whiteness index (Stensby) and yellowness index (ASTM D 1925 and ASTM E 313) were investigated. Scanning electron microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy were used to identify the morphological structure of wool fibres and their atomic content. The chemical damage caused by enzyme was investigated using a fluorescence and a light microscope, and the alkali solubility (ASTM D 1283) was determined. After enzymatic treatment, the wool fibres were dyed at a 2.0% concentration with reactive dyes. Dyeability (K/S) and CIELab values were assessed with a Minolta CM 3600 D spectrophotometer (D65, 10°). The washing fastness of wool fibres was investigated according to TS EN ISO 105-C06 (A1S).     

EFFECT OF GAS DIFFUSION LAYER CHARACTERISTICS AND ADDITION OF PORE-FORMING AGENTS ON THE PERFORMANCE OF POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

The performance of five layer membrane electrode assemblies having different characteristics of gas diffusion layers was determined at 70°C cell temperature and ambient pressure. The maximum power density at 0.6 V was 0.36 W/cm² for the membrane electrode assembly prepared with the gas diffusion layer having minimum thickness (SGL BC 30 type). On the other hand, the maximum power density at 0.5 V was 0.44 W/cm² for the membrane electrode assembly prepared with SGL BC 34 type gas diffusion layer. It was found that resistance of a membrane electrode assembly is strongly dependent on gas diffusion layer thickness. Moreover, membrane electrode assemblies prepared with carbon paper gas diffusion layers resulted in higher performance than the assembly prepared with carbon cloth gas diffusion layer. Addition of pore-forming agents, which were ammonium carbonate, ammonium bicarbonate, ammonium sulfonate, and ammonium oxalate, to the catalyst ink lowered the performance.     

Optimization of atrazine removal from synthetic groundwater by electrooxidation process using titanium dioxide and graphite electrodes

ABSTRACT

Atrazine is used in agriculture and is known for its high toxicity. It therefore poses a risk to surface and ground waters, and human life. In this study, an electrochemical method was optimized for atrazine removal from SGW using TiO₂ and graphite electrodes. A comparison between one factor at a time period optimization and Box-Behnken design (BBD) optimization using RSM was carried out to select the optimum conditions. The results show excellent atrazine removal efficiency (99.70%) and close optimum conditions for both applied methods (pH 7 and 7.4; current 2.5 and 2 A and time 14 and 12.12 min, respectively).     

Physical and chemical properties of tomato, green tea, and ginseng-supplemented corn extrudates produced by conventional extrusion and CO2 injection process

In this study, extrudates were produced from corn flour supplemented with tomato, green tea, and ginseng powder by conventional extrusion and CO₂ injection methods. In conventional extrusion process, the die exit temperatures were adjusted to 80, 110, 130 °C and CO₂ injection method was carried out at 80 °C. In both extrusion methods, the feed moisture, screw speed, and die diameter were kept constant at 20 %, 250 rpm, and 3 mm, respectively. Corn flour was supplemented with tomato powder at three different levels (4, 8, and 12 %), but ginseng and green tea were added only at 8 % level. The bulk density results generally had an inverse relationship with the expansion index values. Higher tomato powder supplementation levels resulted in higher total phenolic compound levels and antioxidant activities. These increases were around 11-fold as compared to control samples in 12 % tomato powder supplementation level at 130 °C extrusion temperature. The results indicated that antioxidant activity increased with increasing extrusion temperature. This increase might be due to higher amount of Maillard reaction products, with antioxidant activity, formed at higher extrusion temperatures. The color (L*, a*, b*) and hydroxymethylfurfural results proved that the rate of Maillard reaction increased at higher extrusion temperatures during the extrusion process. Green tea supplementation resulted in higher total phenolic compounds and antioxidant activity values as compared to tomato and ginseng supplementation under the same extrusion conditions.     

Effect of biogenic substrate concentration on the performance of sequencing batch reactor treating 4-CP and 2,4-DCP mixtures

Effect of a biogenic substrate (peptone) concentration on the performance of sequencing batch reactor (SBR) treating 220 mg/l 4-chlorophenol (4-CP) and 110 mg/l 2,4-dichlorophenol (2,4-DCP) mixtures was investigated. In this context, peptone concentration was gradually decreased from 300 mg/l to null in which chlorophenols were fed to the reactor as sole carbon and energy sources. By this way, the effect of peptone concentration on observed yield coefficient (Y), biomass concentration, chlorophenols and COD removal performances were investigated. Decreasing peptone concentration accompanied with lower biomass concentration led to increase in peak chlorophenol and COD concentrations within the reactor during each SBR cycle. This, in turn, caused noteworthy declines in the removal rates as chlorophenol degradations followed Haldane substrate inhibition model. Also, increased peak chlorophenol concentrations led to the accumulation of 5-chloro-2-hydroxymuconic semialdehyde (CHMS), which is -meta cleavage product of 4-CP. Despite the decreased removal rates, complete chlorophenols and CHMS degradation, in addition to high COD removal efficiencies (>90%), were observed for all studied conditions, even chlorophenols were added as sole carbon and energy sources. Another significant point is that 2,4-DCP at slightly elevated concentrations (>20 mg/l) within the reactor caused a strong competitive inhibition on 4-CP degradation. In SBR, feeding the influent to the reactor within a certain period (i.e. filling period) provided dilution of coming wastewater, which decreased the chlorophenols concentrations to which microorganisms were exposed. Therefore, use of SBR may help to avoid both self and competitive inhibitions in the treatment of 4-CP and 2,4-DCP mixture especially in the presence high biogenic substrate concentrations. In addition, isolation and identification studies have indicated that Pseudomonas sp. and Pseudomonas stutzeri were dominant species in the acclimated mixed culture.