Thermal stability of clinoptilolite rich mineral from Western Anatolia, Turkey and its Ag-exchange forms was investigated.
Parent mineral of different sizes were heated up to 1000°C with heating rate of 2 and 10°C min-1 using differential thermal analyzer (DTA) and thermogravimetric analyzer (TG). Ag exchange was conducted both in conventional
constant temperature waterbath and microwave at 40, 60 and 80°C. The exchanged minerals were then characteized by scanning
electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), DTA and TG.
The particle size and heating rate do not have significant effect on the thermal behavior of the parent mineral and no structural
changes were observed with Ag exchange, only decomposition temperature was lowered. It was finally concluded that, Ag-exchanged
clinoptilolite rich minerals were less thermally stable compared to parent mineral that does not affect their use for possible
The adsorption kinetics of H2O in a clinoptilolite rich zeolitic tuff was experimentally investigated at 18°C. In the identification of the diffusion mechanism
the isothermal adsorption model equation was used. It was found out that the intraparticle mass transfer becomes more dominant
over the heat transfer with increase in particle size and the adsorptive dose pressure. Although initially intraparticle mass
transfer was the controlling resistance later external heat transfer also contributes to the transfer mechanism.
DNA adsorbed very low amount of water at low relative humidities, amount of adsorption increased to 140% at 98% relative humidity
at 25°C. Heat of adsorption was 109 kJ mol-1 H2O for the increase of moisture content from 0 to 1.96%. At higher moisture contents the heat released approached heat of condensation
of water vapour on free liquid surface, 40 kJ mol-1 H2O.
Authors:D. Balköse, F. Özkan, S. Ulutan, and S. Ülkü
Water vapour adsorption on polymers affects their processing behaviour and useful properties. Water vapour adsorption on organic polymers, silk, Nylon 6 fibres in undrawn and permanent set forms, polyester micro fibres, plasticised PVC films with 60 phr dioctylphthalate (DOP) and inorganic polymer sepiolite particles were investigated in this study. The materials were examined using the BET equation. The surface areas of silk, cast Nylon 6 and muss Nylon 6 were determined as 108, 46 and 23 m2 g–1, respectively. Sepiolite did not fit BET equation. Polyester and PVC adsorbed very small amounts of moisture.
Authors:M. Gönen, D. Balköse, F. İnal, and S. Ülkü
In this research, the effects of zinc stearate addition on paraffin wax degradation were investigated by differential scanning
calorimetry (DSC) and thermogravimetry (TG). The apparent activation energies of wax decomposition in nitrogen and air atmospheres
were determined as 76 and 37 kJ mol−1, respectively applying Kissinger method to TG data. The degradation rate constants of paraffin containing zinc stearate (0.1–0.5%)
were found to be almost two times greater than that of paraffin only in air atmosphere. However, zinc stearate did not affect
the rate constants in nitrogen significantly.
Authors:B. Erdoğan, A. Seyhan, Y. Ocak, M. Tanoğlu, D. Balköse, and S. Ülkü
The cure kinetics of epoxy resin and epoxy resin containing 10 mass% of natural zeolite were investigated using differential
scanning calorimetry (DSC). The conformity of the cure kinetic data of epoxy and epoxy-zeolite system was checked with the
auto-catalytic cure rate model. The results indicated that the hydroxyl group on the zeolite surface played a significant
role in the autocatalytic reaction mechanism. This group was able to form a new transition state between anhydride hardener
and epoxide group. The natural zeolite particles acted as catalyst for the epoxy system by promoting its curing rate.
Authors:S. Öz, R. Kurtaran, C. Arıcı, Ü. Ergun, F. Kaya, K. Emregül, O. Atakol, and D. Ülkü
Bis-N,N′(salicylidene)-2,2′-dimethyl-1,3-propanediamine (LDMH2) has a high tendency to form polynuclear complexes. Two trinuclear complexes were obtained using this ligand and azide ions;
(CuLDM)2 · Mn(N3)2 · (DMF)2, [(C19H20N2O2Cu)2 · Mn(N3)2 · (C3H7NO)2] and (CuLDM)2 · Cd(N3)2 · (DMF)2, [(C19H20N2O2Cu)2 · Cd(N3)2 · (C3H7NO)2]. The structures were identified with X-ray methods. TG and DSC methods were also employed to these complexes. Studies showed
the (CuLDM)2 · Mn(N3)2 · (DMF)2 and (CuLDM)2 · Cd(N3)2 · (DMF)2 to be non-linear. Also μ-bridges were not encountered for the azide ions but were seen to form between the Cu and other metal
via phenolic oxygens. Thermal analysis showed exothermic degradation of the azide ions destroying the trinuclear structure.
Although azide containing structures show explosive characteristics, this was not observed for the present compounds.
Authors:S. Öz, M. Kunduracı, R. Kurtaran, Ü. Ergun, C. Arıcı, M. Akay, O. Atakol, K. Emregül, and D. Ülkü
In the first instance, mononuclear Cu(II) complexes are prepared with bis-N,N′(salicylidene)-1.3-propanediamine and derivatives. After that, these mononuclear complexes are combined with μ-bridges, by
the help of azide ions, to obtain the tetranuclear complexes. Prepared complexes are characterised using IR spectroscopy,
elemental analysis, and X-Ray techniques. In addition, the complexes are further analysed via TG and DSC. Molecular models
of two of the nine prepared complexes are determined using X-Ray diffraction methods. The two terminal copper ions are observed
to be in square pyramide coordination sphere between two oxygens of the organic ligand, two iminic nitrogens and an oxygen
of the solvent while the other two cupper ions are observed to be in square pyramide coordination sphere between the fenolic
oxygens of the organic ligand and the nitrogen donors of the three azide ions. It is found that the fenolic oxygens form μ-bridge
and two azide ions are monodentate coordinated. In the TG analyses, the complexes are observed to decompose in a highly exothermic
manner at about 200 °C. This thermal reaction is partially similar to that of explosive molecules and the data from DSC proved
that the liberated heat is at explosive material levels.