Authors:İsa Doğan Atik, B. Özen, and F. Tıhmınlıoğlu
The novel film structure of corn-zein coated on polypropylene (PP) synthetic film for packaging industry was developed to
examine the feasibility of resulting coated films as an alternative water barrier performance for food packaging. The effects
of coating formulation (solvent, corn-zein, plasticizer concentration and plasticizer type) on final properties of films were
observed. Corn-zein is the most important protein of corn and has good film forming property. Composites structures of PP
films coated with corn-zein were obtained through a simple solvent casting method. Polyethylene glycol (PEG) and glycerol
(GLY) were used as plasticizer to increase film flexibility. Statistical analysis based on full factorial design was performed
to observe coating formulation effects. The high water vapour barriers were obtained for films coated with coating formulation
consisting of higher amounts of corn-zein plasticized by GLY. The lower glass transition temperatures (Tg) of films were obtained by plasticization of films and Tg decreased by increasing plasticizer content. The statistical analysis defined the key parameters of coating formulation that
had major effects on the final properties of coated PP films as corn-zein, plasticizer concentration and plasticizer type.
In conclusion, corn-zein coatings could have potential as an alternative to conventional synthetic polymers used in composite
multilayer structures for food packaging applications.
Authors:F. Doǧan, S. Gülcemal, M. Yürekli, and B. Çetinkaya
The imidazolinium and benzimidazolium bromide salts with pentafluor substituents on N atom were synthesized. The structures
of imidazolinium and benzimidazolium bromide salts obtained were conformed by 1H and 13C NMR, 19F NMR and elemental analysis. It was found that pyrolytic decomposition occurs with melting in salts. The imidazolinium and
benzimidazolium bromide salts were studied by TG-DTG and DTA from ambient temperature to 1000°C in nitrogen atmosphere. The
decomposition occurred mainly in one stage and the values of activation energy E, frequency factor A, reaction order n, enthalpy change ΔH#, entropy change ΔS# and Gibbs free energy ΔG#, of the thermal decomposition were calculated by means of Coats-Redfern (CR), MacCallum-Tanner (MC) and van Krevelen (vK)
methods. The activation energy value obtained by CR and MC methods were in good agreement with each other while those obtained
by vK were found to be 10–12 kJ mol−1 larger.
Authors:F. Doğan, M. Ulusoy, Ö. Öztürk, İ. Kaya, and B. Salih
The thermal decomposition kinetics of sterically hindered salen type ligand (L) and its metal complexes [M=Co(II), Ni(II), Cu(II)] were investigated by thermogravimetric analysis. A direct insertion probe-mass spectrometer (DIP-MS)
was used for the characterization of metal complexes of L and all fragmentations and stable ions were characterized. The thermogravimetry and differential thermogravimetry (TG-DTG)
plots of salen type salicylaldimine ligand and complexes showed a single step.
The kinetic analysis of thermogravimetric data was performed by using the invariant kinetic parameter method (IKP). The values
of the invariant activation energy, Einv and the invariant pre-exponential factor, Ainv, were calculated by using Coats-Redfern (CR) method. The thermal stabilities and activation energies of metal complexes of
sterically hindered salen type ligand (L) were found as Co(II)>Cu(II)>Ni(II)>L and ECu>ENi>ECo>L. Also, the probabilities of decomposition functions were investigated. The diffusion functions (Dn) are most probable for the thermal decomposition of all complexes.
Authors:F. Doğan, O. Dayan, M. Yürekli, and B. Çetinkaya
Thermal behaviors of mono-and binuclear Ru(II)-pydim complexes: [PydimCl2RuL] (Pydim: pyridine-2,6-diimine; 2: L=NCMe; 3: L=PPh3) and [PydimCl2Ru(L-L)RuCl2Pydim] (4: L-L=pyrazine; 5: L-L=4,4′-bipyridine) have been studied in nitrogen atmosphere using TG/DTG and DTA techniques.
The decompositions of complexes occur in stepwise. The values of activation energy, Ea, and reaction order, n of the thermal decomposition were calculated by means of several methods such as Coats-Redfern (CR), MacCallum-Tanner (MT),
Horowitz-Metzger (HM), van Krevelen (vK), Madhusudanan-Krishnan-Ninan (MKN) and Wanjun-Yuwen-Hen-Cunxin (WYHC) based on the
single heating rate. Most appropriate method was determined for each decomposition step according to the least-squares linear