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Static and Dynamic Mechanical Properties of Cotton/Epoxy Green Composites

Koyuncu M., Karahan M., Karahan N., Shaker K., Nawab Y.

Fibres & Textiles in Eastern Europe

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2016

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Vol. 24, no. 4 (118)

105--111

EN

A study on the effect of alkaline treatment on the mechanical properties of cotton fabric reinforced epoxy composites is presented in this paper. One hour treatment of cotton fabric was performed using three different concentrations of sodium hydroxide (NaOH) solution. 1% NaOH treated fabric reinforced composites exhibited maximum improvement in tensile strength. It was concluded that the said NaOH concentration improves interfacial adhesion between the cotton fabric and epoxy resin. Moreover the morphology of the fracture surface, evaluated by scanning electron microscopy (SEM), indicated that surface treatment can yield better adhesion between the fabric and matrix, demonstrating the effectiveness of the treatment. The dynamic mechanical analysis (DMA) results revealed that alkali treated (1% and 3% NaOH) fabric composites exhibit higher storage moduli and glass transition temperature (Tg) values as compared to the untreated fabric composites. However, for all the composite specimens, the storage modulus decreased with increasing temperature (25 - 100 °C). Tg values of 50.9, 56.7, 52.8 and 37.7 °C were recorded for the untreated and (1%, 3% and 5%) treated composites, respectively. The tan δ values decreased for all the composites with increasing temperature, indicating enhanced interactions between the polymer matrix and fabric reinforcement.

PL

Badano wpływ obróbki alkalicznej na mechaniczne właściwości tkanin bawełnianych wzmacniających kompozyty epoksydowe. Stosowano jednogodzinną obróbkę tkanin bawełnianych przy stosowaniu trzech różnych stężeń NaOH. Stwierdzono, że tkaniny poddane działaniu 1% NaOH wykazują najlepsze właściwości biorąc pod uwagę wytrzymałość na rozciąganie. Stwierdzono, że obróbka alkaliczna polepsza międzyfazową adhezję pomiędzy bawełnianą tkaniną i żywicą epoksydową. Oprócz tego stwierdzono, badając morfologię przełomów za pomocą SEM, że obróbka powierzchniowa pozwala na uzyskanie lepszej adhezji pomiędzy tkaniną a matrycą epoksydową. Stwierdzono również zmiany składowej rzeczywistej modułu zespolonego oraz wartości temperatury i przemiany szklistej. Ze wzrostem temperatury zmienia się również tan δ dla wszystkich kompozytów potwierdzając polepszającą się interakcję pomiędzy matrycą polimerową i włóknistym wzmocnieniem.

2

Thermodynamics and adsorption studies of dye (rhodamine-b) onto natural diatomite

Koyuncu M., Kul A. R.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 2

631--643

EN

Thermodynamics and adsorption studies were conducted with a dye of rhodamine-B on natural diatomite. Adsorption of the dye was investigated with an initial dye concentration at pH 8±0.2, 303, 313 and 323 K. The adsorption experiments were carried out isothermally at three different temperatures. The Langmuir and Freundlich isotherm models were used to describe the equilibrium data and the results were discussed in details. The kinetic data agreed with the pseudo-first order model with rate constants (k2) in the range of 3.05–1.59.10–1 g/mg min. The thermodynamic parameters such as standard free energy, entropy change and enthalpy were calculated for natural diatomite. These values showed that adsorption of rhodamine-B on natural diatomite was a spontaneous and endothermic process.

3

Colour removal from aqueous solution of tar-chromium green 3G dye using natural diatomite

Koyuncu M.

Physicochemical Problems of Mineral Processing

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2012

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Vol. 48, iss. 2

485-494

EN

Removal of Tar-Chromium Green 3G dye from aqueous solution at different dye concentrations, different temperatures and adsorbent doses has been studied. It was seen that the maximum of 88% adsorption has been achieved from the wastewater using 3.0 g material at 30oC temperature for shaking time of 60 min.The adsortion isotherms are described by means of the Langmuir and Freudlich isotherms at different temperatures of 25, 30 and 35C, and the results were discussed. The equilibrium data satisfied both the Langmuir and Freundlich models. Moreover, thermodynamic parameters such as ΔH, ΔS and ΔG were also studied. It was found that the values of standard free energy (ΔG) and the values of standard enthalpy (ΔH) were negative and entropy (ΔS) was found to be positive. Thermodynamic studies showed that the reaction for uptake by diatomite is exohtermic in nature.The results of this study showed that diatomite could be employed as effective and low-cost materials for the removal of the dye from aqueous solution.