Authors:D. Balköse, T. Egbuchunam, and F. Okieimen
Soaps are a class of surface active compounds derived from natural oils and fats. Double decomposition reactions permit the
synthesis of metallic soaps, which are long-chain carboxylates of metal ions, from alkaline ones such as sodium, potassium
or ammonium soaps. Metallic soaps are commercially important as they find use in diverse applications such as driers in paints
or inks, components of lubricating greases, heat stabilizers for plastics (especially PVC), catalysts and water proofing agents,
fuel additives and cosmetic products amongst others. Many of these applications are related to the thermal properties of these
compounds and the thermal behaviour of metal soaps in terms of decomposition processes is of great importance. Rubber seed
oil (RSO) which is an unsaturated triglyceride abundantly available in Nigeria, India and Australia is an excellent starting
material for metal soaps. In this study rubber seed oil having 2.2% myristic acid, 7.6% palmitic acid, 10.7% stearic acid,
20.61% oleic acid, 36.62% linoleic acid, 22.5% linolenic acid was used in making barium, calcium, cadmium and zinc soaps.
The thermal behaviour of soaps (Ba, Ca, Cd and Zn) of rubber seed oil for use as additives in the processing of poly(vinyl
chloride) (PVC) was investigated by thermal gravimetry and differential scanning calorimetry. The stability of the soaps was
examined by thermogravimetry up to 873 K at a constant heating rate of 10 °C min−1. The soaps were found to be thermally stable up to 473 K as they recorded less than 5% mass loss at this temperature with
values of apparent activation energy for decomposition varying from 52 to 96 kJ mol−1. Differential scanning calorimetric studies of the soaps revealed melting and decomposition behaviour of metal soaps.
Part I of the short survey covers definitions of air humidity and the respective measuring methods such as hygrometry, psychrometry,
dew point measurement, LIDAR hygrometry and humidity sensors. Techniques based on property changes of matter with adsorbed
moisture from air are reviewed.
Part II covers the most common methods of measuring the humidity of solid material. State of water near solid surfaces, gravimetric
measurement of material humidity, measurement of water sorption isotherms, chemical methods for determination of water content,
measurement of material humidity via the gas phase, standardisation, cosmonautical observations are reviewed.
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. Berkün, D. Balköse, F. Tıhmınlıoǧlu, and S. Altınkaya
Two types of films consisting of sodium salt of carboxymethyl cellulose (NaCMC) and hydroxypropyl cellulose (HPC) as film
forming materials and glycerin as plasticizer were prepared, characterized and their water vapour sorption properties were
The water sorption isotherms of the films were measured using a magnetic suspension balance. Results show that diffusion of
water vapour in NaCMC based film is faster than that in HPC based films, due to the heterogeneous structure and larger pore
dimensions of the NaCMC films.
Authors:E. Robens, P. Klobes, D. Balköse, S. Amarasiri, and A. Jayaweera
A short survey is given on mass units and recommendations on the proper use of the notations mass and weight.Whereas mass
is an inertial physical quantity in classical mechanics, weight is a force due to the gravitational field and depending on
the geographic situation.
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: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: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.