Sevdiye Savrık - Academia.edu (original) (raw)
Papers by Sevdiye Savrık
Drying Technology, 2021
Zinc borate is an important additive to polymers and lubricants. The process variables such as re... more Zinc borate is an important additive to polymers and lubricants. The process variables such as reactant concentration, presence of template in precipitating medium and drying method determine the c...
The formation of the first membrane, the swelling of the crystal by incoming water from the semip... more The formation of the first membrane, the swelling of the crystal by incoming water from the semipermeable membrane and the formation of irregular shaped branches were observed by optical microscopy, when zinc sulfate heptahydrate crystals were immersed in saturated borax solution. The powders obtained by mixing dilute aqueous borax and zinc sulfate solutions had B, O, Na, S and Zn elements. Presence of Na Zn 1/2B4O7.xH2O was indicated by EDX analysis. The molar ratio of B 2O3/ZnO in powders was around 2. FTIR analysis indicated the ratio of absorbance values of asymmetric stretching vibrations of B(3)-O at 1351 cm-1 to that of B (4)-O at 1026 cm-1 increased with their heating time at 90oC during their preparation. X-ray diffraction patterns indicated the presence of Zn(OH)2 and Zn 4(OH)6(SO4)·4H2O. The zinc borate compounds in the powders were not crystalline since no sharp peaks related to zinc borates were present in x-ray diffraction diagram. There were two mass loss steps in TG ...
Journal of the Turkish Chemical Society, Section A: Chemistry, Dec 25, 2017
Http Dx Doi Org 10 1080 07373937 2012 701258, Nov 13, 2012
ABSTRACT The dehydration behaviors of two different hydrated zinc borate species, Zn[B3O3(OH)5] ·... more ABSTRACT The dehydration behaviors of two different hydrated zinc borate species, Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3], which are industrially important flame retardants, were studied by thermal gravimetric(TG) analysis and in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Dehydration onset temperatures of Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3] were 129 and 320°C, respectively, at a 10°C/min ramp rate. A very small amount of boric acid was volatilized in addition to water vapor when both samples were heated at 250°C. A significant amount of water vapor was adsorbed by Zn[B3O3(OH)5] · H2O from air at 25°C. However, Zn[B3O4(OH)3] adsorbed a very small amount of water under the same conditions. Both zinc borates did not have a tendency to cake during storage.
Journal of Vinyl and Additive Technology, 2005
Abstract The synergistic effect of metal soaps (zinc stearate and calcium stearate) and/or natura... more Abstract The synergistic effect of metal soaps (zinc stearate and calcium stearate) and/or natural zeolite (clinoptilolite) on PVC thermal stability was investigated. For this purpose, PVC plastisol was prepared by mixing poly (vinyl chloride)(PVC) and dioctyl phthalate ( ...
Journal of Thermal Analysis and Calorimetry, 2011
Lubricating oil additives based on boron compounds are promising materials for lubrication due to... more Lubricating oil additives based on boron compounds are promising materials for lubrication due to their tribological advantages such as antiwear efficiency, good film strength, and high temperature resistance. This article deals with the preparation of zinc borate particles that are well dispersed and colloidally stabilized in mineral oil. This method starts with preparing two inverse emulsions (water-in-oil) with sorbitan monostearate
Journal of Applied Polymer Science, 2010
Drying Technology, 2012
ABSTRACT The dehydration behaviors of two different hydrated zinc borate species, Zn[B3O3(OH)5] ·... more ABSTRACT The dehydration behaviors of two different hydrated zinc borate species, Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3], which are industrially important flame retardants, were studied by thermal gravimetric(TG) analysis and in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Dehydration onset temperatures of Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3] were 129 and 320°C, respectively, at a 10°C/min ramp rate. A very small amount of boric acid was volatilized in addition to water vapor when both samples were heated at 250°C. A significant amount of water vapor was adsorbed by Zn[B3O3(OH)5] · H2O from air at 25°C. However, Zn[B3O4(OH)3] adsorbed a very small amount of water under the same conditions. Both zinc borates did not have a tendency to cake during storage.
Chemical Engineering Communications, 2008
Journal of Thermal Analysis and Calorimetry, 2010
The effect of emulsion process formulation ingredients on the morphology, structure, and properti... more The effect of emulsion process formulation ingredients on the morphology, structure, and properties of polyvinyl chloride (PVC) powder has been considered in this study. PVC powder was extracted with ethanol and films were obtained by solvent casting from tetrahydrofurane. Characterization of powders, films, and ethanol extract was performed through FTIR spectroscopy, DSC, AFM, SEM, EDX analysis, methylene blue, and nitrogen adsorption. PVC powder was composed of spheres of a large particle size range from 10 nm to 20 μm as shown by SEM. The specific surface area of the PVC powder was determined as 16 and 12 m2 g−1 from methylene blue adsorption at 25 °C and from N2 adsorption at −196 °C, respectively. AFM indicated the surface roughness of the films obtained by pressing the particles was 25.9 nm. Density of PVC powder was determined by helium pycnometry as 1.39 g cm−3. FTIR spectroscopy indicated that it contained carbonyl and carboxylate groups belonging to additives such as surface active agents, plasticizers, and antioxidants used in production of PVC. These additives were 1.6% in mass of PVC as determined by ethanol extraction. EDX analysis showed PVC particles surfaces were coated with carbon-rich materials. The coatings had plasticizer effect since, glass transition temperature was lower than 25 °C for PVC powder and it was 80 °C for ethanol extracted powders as found by using differential scanning calorimetry. These additives from polymerization process made PVC powder more thermally stable as understood from Metrom PVC thermomat tests as well.
Drying Technology, 2021
Zinc borate is an important additive to polymers and lubricants. The process variables such as re... more Zinc borate is an important additive to polymers and lubricants. The process variables such as reactant concentration, presence of template in precipitating medium and drying method determine the c...
The formation of the first membrane, the swelling of the crystal by incoming water from the semip... more The formation of the first membrane, the swelling of the crystal by incoming water from the semipermeable membrane and the formation of irregular shaped branches were observed by optical microscopy, when zinc sulfate heptahydrate crystals were immersed in saturated borax solution. The powders obtained by mixing dilute aqueous borax and zinc sulfate solutions had B, O, Na, S and Zn elements. Presence of Na Zn 1/2B4O7.xH2O was indicated by EDX analysis. The molar ratio of B 2O3/ZnO in powders was around 2. FTIR analysis indicated the ratio of absorbance values of asymmetric stretching vibrations of B(3)-O at 1351 cm-1 to that of B (4)-O at 1026 cm-1 increased with their heating time at 90oC during their preparation. X-ray diffraction patterns indicated the presence of Zn(OH)2 and Zn 4(OH)6(SO4)·4H2O. The zinc borate compounds in the powders were not crystalline since no sharp peaks related to zinc borates were present in x-ray diffraction diagram. There were two mass loss steps in TG ...
Journal of the Turkish Chemical Society, Section A: Chemistry, Dec 25, 2017
Http Dx Doi Org 10 1080 07373937 2012 701258, Nov 13, 2012
ABSTRACT The dehydration behaviors of two different hydrated zinc borate species, Zn[B3O3(OH)5] ·... more ABSTRACT The dehydration behaviors of two different hydrated zinc borate species, Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3], which are industrially important flame retardants, were studied by thermal gravimetric(TG) analysis and in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Dehydration onset temperatures of Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3] were 129 and 320°C, respectively, at a 10°C/min ramp rate. A very small amount of boric acid was volatilized in addition to water vapor when both samples were heated at 250°C. A significant amount of water vapor was adsorbed by Zn[B3O3(OH)5] · H2O from air at 25°C. However, Zn[B3O4(OH)3] adsorbed a very small amount of water under the same conditions. Both zinc borates did not have a tendency to cake during storage.
Journal of Vinyl and Additive Technology, 2005
Abstract The synergistic effect of metal soaps (zinc stearate and calcium stearate) and/or natura... more Abstract The synergistic effect of metal soaps (zinc stearate and calcium stearate) and/or natural zeolite (clinoptilolite) on PVC thermal stability was investigated. For this purpose, PVC plastisol was prepared by mixing poly (vinyl chloride)(PVC) and dioctyl phthalate ( ...
Journal of Thermal Analysis and Calorimetry, 2011
Lubricating oil additives based on boron compounds are promising materials for lubrication due to... more Lubricating oil additives based on boron compounds are promising materials for lubrication due to their tribological advantages such as antiwear efficiency, good film strength, and high temperature resistance. This article deals with the preparation of zinc borate particles that are well dispersed and colloidally stabilized in mineral oil. This method starts with preparing two inverse emulsions (water-in-oil) with sorbitan monostearate
Journal of Applied Polymer Science, 2010
Drying Technology, 2012
ABSTRACT The dehydration behaviors of two different hydrated zinc borate species, Zn[B3O3(OH)5] ·... more ABSTRACT The dehydration behaviors of two different hydrated zinc borate species, Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3], which are industrially important flame retardants, were studied by thermal gravimetric(TG) analysis and in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Dehydration onset temperatures of Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3] were 129 and 320°C, respectively, at a 10°C/min ramp rate. A very small amount of boric acid was volatilized in addition to water vapor when both samples were heated at 250°C. A significant amount of water vapor was adsorbed by Zn[B3O3(OH)5] · H2O from air at 25°C. However, Zn[B3O4(OH)3] adsorbed a very small amount of water under the same conditions. Both zinc borates did not have a tendency to cake during storage.
Chemical Engineering Communications, 2008
Journal of Thermal Analysis and Calorimetry, 2010
The effect of emulsion process formulation ingredients on the morphology, structure, and properti... more The effect of emulsion process formulation ingredients on the morphology, structure, and properties of polyvinyl chloride (PVC) powder has been considered in this study. PVC powder was extracted with ethanol and films were obtained by solvent casting from tetrahydrofurane. Characterization of powders, films, and ethanol extract was performed through FTIR spectroscopy, DSC, AFM, SEM, EDX analysis, methylene blue, and nitrogen adsorption. PVC powder was composed of spheres of a large particle size range from 10 nm to 20 μm as shown by SEM. The specific surface area of the PVC powder was determined as 16 and 12 m2 g−1 from methylene blue adsorption at 25 °C and from N2 adsorption at −196 °C, respectively. AFM indicated the surface roughness of the films obtained by pressing the particles was 25.9 nm. Density of PVC powder was determined by helium pycnometry as 1.39 g cm−3. FTIR spectroscopy indicated that it contained carbonyl and carboxylate groups belonging to additives such as surface active agents, plasticizers, and antioxidants used in production of PVC. These additives were 1.6% in mass of PVC as determined by ethanol extraction. EDX analysis showed PVC particles surfaces were coated with carbon-rich materials. The coatings had plasticizer effect since, glass transition temperature was lower than 25 °C for PVC powder and it was 80 °C for ethanol extracted powders as found by using differential scanning calorimetry. These additives from polymerization process made PVC powder more thermally stable as understood from Metrom PVC thermomat tests as well.