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  • Author or Editor: F. Doğan x
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Abstract  

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 (T g) of films were obtained by plasticization of films and T g 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.

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Abstract  

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.

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Abstract  

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.

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Abstract  

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, E a, 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 regression.

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