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Papers by elif vargun

Electrochimica Acta, 2014

Abstract A fluorescent pyrrole derivative bearing a dansyl substituent was prepared by a simple s... more Abstract A fluorescent pyrrole derivative bearing a dansyl substituent was prepared by a simple synthetic route and electropolymerized onto Indium Tin Oxide (ITO) electrodes. The presence of the dansyl group in the monomer precursor prevents the electropolymerization in usual systems, such as (C 4 H 9 ) 4 NBF 4 in acetonitrile (CH 3 CN). For this reason, it was added 20% boron trifluoride diethyl etherate (BFEE) to this system, to achieve electropolymerization. The resulting poly[3-( N -pyrrolyl)propyl dansylglycinate] (PPyPDG) films displayed electrochromic behavior. Their color varied from greenish-yellow, in the neutral state, to greyish-green, in the oxidized state; moreover PPyPDG is a good green light emitter material. Therefore, PPyPDG films might be potentially applicable in displays and optoelectronic devices.

Journal of Electroanalytical Chemistry

Mugla Journal of Science and Technology, 2017

The improved dispersion of clay minerals has an essential role for polymer clay nanocomposite man... more The improved dispersion of clay minerals has an essential role for polymer clay nanocomposite manufacturing. In this regard, different organomodifications of clay have been attempted to obtain intercalated/exfoliated structures of composites. In present study, Çanakkale bentonite was organically modified by four different quaternary ammonium salts: tetramethylammonium chloride (TMAC), hexadecylpyridinium chloride (HDPC), hexadecyltrimethylammonium bromide (HDAB), phenyltrimethylammonium chloride (PMAC). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis and thermogravimetric analysis (TGA) were performed to characterize the organobentonites. The results revealed that there is an increment of basal spacing of bentonite with HDAB and HDPC salts from 14.9 Å to 20.7 Å and 21.4 Å, respectively. However, other modifiers cannot lead to significant changes in d-spacings.

Az yoğunluklu polietilen (AYPE) tarımda yaygın olarak kullanılan plastiklerden biridir ve LDPE’de... more Az yoğunluklu polietilen (AYPE) tarımda yaygın olarak kullanılan plastiklerden biridir ve LDPE’den üretilen malç filmlerin bozunabilirliği termoplastik nişasta (TPN) eklenmesi ile artırılmaktadır. Bu çalışmada, bileşiminde %20’den %40’a kadar değişen oranlarda TPN bulunan TPN/LDPE karışımları çift vidalı karıştırıcı kullanılarak hazırlandı. TPN’nın ara yüzey yapışmasını geliştirmek ve matris içinde daha iyi dağılmasını sağlamak için, sitrik asit ve stearik asit uyumlulaştırıcıları ilave edildi. Bozunmayı hızlandırmak için kobalt(II) asetilasetonat pro-oksidan olarak kullanılmıştır. Malç filmler bozunması için 180 gün Coriolus versicolor (L.) Quél ve Postia plasenta (Fr.) M.J. Larsen & Lombard ile aşılanmış topraklara gömüldü. Filmlerin kimyasal yapılarındaki değişiklikler toprağa gömülmeden önce ve sonra FTIR spektroskopisi ile değerlendirildi. Tüm örneklerin ağırlık kaybı 180 gün biyobozunmadan sonra ölçüldü ve artan nişasta içeriği ile ağırlık kaybının hızlandığı görüldü. Uyumlaşt...

Materials Science and Engineering: C, 2021

In transdermal drug delivery applications uniform drug distribution and sustained release are of ... more In transdermal drug delivery applications uniform drug distribution and sustained release are of great importance to decrease the side effects. In this direction in the present research, vanillin crosslinked chitosan (CS) and polyvinyl alcohol (PVA) blend based matrix-type transdermal system was prepared by casting and drying of aqueous solutions for local delivery of enrofloxacin (ENR) drug. Subsequently, the properties including the morphology, chemical structure, thermal behavior, tensile strength, crosslinking degree, weight uniformity, thickness, swelling and drug release of the CS-PVA blend films before and after crosslinking were characterized. In vitro drug release profiles showed the sustained release of ENR by the incorporation of vanillin as a crosslinker into the CS-PVA polymer matrix. Furthermore, the release kinetic profiles revealed that the followed mechanism for all samples was Higuchi and the increase of vanillin concentration in the blend films resulted in the change of diffusion mechanism from anomalous transport to Fickian diffusion. Overall, the obtained results suggest that the investigated vanillin crosslinked CS-PVA matrix-type films are potential candidates for transdermal drug delivery system.

Journal of Electronic Materials

Conductive polymers, such as polyaniline (PANI) and polypyrrole (PPy), are widely used in the des... more Conductive polymers, such as polyaniline (PANI) and polypyrrole (PPy), are widely used in the design of supercapacitors because of their high pseudo-capacitive performance as well as facile synthesis and low cost. In this study, hybrid aerogels based on reduced graphene oxide and ZnMn2O4 were modified by PANI and PPy. The 3D structure of the hybrid aerogels was obtained by using a one-step hydrothermal co-assembly method. Then, aniline and pyrrole were polymerized on and within the structure of the hybrid aerogel through in situ polymerization. The electrochemical properties of the hybrid aerogels were studied via cyclic voltammetry and galvanostatic charge–discharge testing to identify the effects of conductive polymers on the electrochemical properties of materials. It has been established that PANI and PPy facilitate an increase of the specific capacitance of rGO/ZnMn2O4 aerogels up to 297.8 F/g and 108.24 F/g at 0.2 A/g scan rate, respectively.

International Journal of Polymeric Materials and Polymeric Biomaterials

Nanomaterials

To improve Li storage capacity and the structural stability of Ti3C2 MXene-based electrode materi... more To improve Li storage capacity and the structural stability of Ti3C2 MXene-based electrode materials for lithium-ion batteries (LIBs), a facile strategy is developed to construct three-dimensional (3D) hierarchical porous Ti3C2/bimetal-organic framework (NiCo-MOF) nanoarchitectures as anodes for high-performance LIBs. 2D Ti3C2 nanosheets are coupled with NiCo-MOF nanoflakes induced by hydrogen bonds to form 3D Ti3C2/NiCo-MOF composite films through vacuum-assisted filtration technology. The morphology and electrochemical properties of Ti3C2/NiCo-MOF are influenced by the mass ratio of MOF to Ti3C2. Owing to the interconnected porous structures with a high specific surface area, rapid charge transfer process, and Li+ diffusion rate, the Ti3C2/NiCo-MOF-0.4 electrode delivers a high reversible capacity of 402 mAh g−1 at 0.1 A g−1 after 300 cycles; excellent rate performance (256 mAh g−1 at 1 A g−1); and long-term stability with a capacity retention of 85.7% even after 400 cycles at a h...

Journal of Applied Polymer Science

Maderas. Ciencia y tecnología

This study investigated the thermal properties of Oriental beech (Fagus orientalis) treated with ... more This study investigated the thermal properties of Oriental beech (Fagus orientalis) treated with (NH 4) 2 H-PO 4 , K 2 HPO 4 , NH 4 Cl and (NH 4) 2 SO 4 salts and their mixtures (1:1; w/w) aqueous solutions at 3% concentrations. The effects of different inorganic salts fire retardants on the thermal degradation characteristics of wood samples were evaluated by thermogravimetric analysis (TGA). Based on the TGA curve for untreated beech wood, weight loss takes place at three distinct steps. The impregnation of inorganic salts resulted in higher char yields and additional thermal degradation steps were identified. The highest char yield (80%) was obtained from (NH 4) 2 HPO 4-K 2 HPO 4 mixture impregnated sample. Salt mixtures containing phosphates ((NH 4) 2 HPO 4 and K 2 HPO 4) have remarkable effects on thermal stability of beech wood, whereas NH 4 Cl salt lowered the decomposition temperatures and char yield.

Journal of Macromolecular Science Pure and Applied Chemistry, Jul 30, 2010

ABSTRACT The degradation of poly(hydroxyethyl methacrylate), PHEMA obtained by γ -radiation induc... more ABSTRACT The degradation of poly(hydroxyethyl methacrylate), PHEMA obtained by γ -radiation induced polymerization of HEMA in aqueous solution, was studied. The polymer was a gel type and insoluble in common organic solvents. The DSC thermogram of the polymer gave a Tg value at 88.2°C and an endothermic peak showed further polymerization or crosslinking at 110–160°C. The degradation observed in TGA was a depolymerization type. However, the FT-IR of TGA fragments showed no monomer, which was degraded further. The degradation of monomer was studied by the GC-MS method. Similar results were also observed.

Hacettepe Journal of Biology and Chemistry

K ısmen bozunabilen malç filmleri hazırlamak için az yoğunluklu polietilen (AYPE), termoplastik n... more K ısmen bozunabilen malç filmleri hazırlamak için az yoğunluklu polietilen (AYPE), termoplastik nişasta (TPN) ile çift vidalı ekstruder yardımıyla karıştırıldı. Bu çalışmada, demir(III) stearat ve manganez(II) stearat pro-oksidan olarak kullanılmışve farklı pro-oksidanların karışımların bozunması üzerindeki etkisi incelenmiştir. Malç filmler Coriolus versicolor (L.) Quel ile aşılanmış toprağa gömülerek 180 gün boyunca degrede edilmiştir. Filmlerin kimyasal yapıları FTIR spektroskopisi ile belirlenmiş ve tüm numunelerin ağırlık kaybı toprakta bozunma öncesi ve sonrası ölçülmüştür. İki farklı pro-oksidanın, malç karışımların ısıl ve germe özellikleri üzerine etkisi TGA ve mekanik analiz ile tespit edilmiştir. Demir (III) stearat ve sitrik asitin birlikte kullanılmasıyla sinerjik bir etki gözlenmiştir. Her ikisinin birlikte kullanıldığı karışımlarda TPN'nin yüksek ısıl kararlılık gösterdiği bulunmuştur. Ayrıca, mekanik özelliklerinde belirgin düzelme gözlenmiştir. Bununla birlikte, manganez(II) stearat sitrik asit ile birlikte kullanıldığında stearik asitli karışımlarına kıyasla daha zayıf mekanik özellikler göstermiştir. Anahtar Kelimeler AYPE, termoplastik nişasta, pro-oksidan, demir stearat, manganez(II) stearat.

A z yoğunluklu polietilen (AYPE) tarımda yaygın olarak kullanılan plastiklerden biridir ve LDPE'd... more A z yoğunluklu polietilen (AYPE) tarımda yaygın olarak kullanılan plastiklerden biridir ve LDPE'den üretilen malç filmlerin bozunabilirliği termoplastik nişasta (TPN) eklenmesi ile artırılmaktadır. Bu çalışmada, bileşiminde %20'den %40'a kadar değişen oranlarda TPN bulunan TPN/LDPE karışımları çift vidalı karıştırıcı kullanılarak hazırlandı. TPN'nın ara yüzey yapışmasını geliştirmek ve matris içinde daha iyi dağılmasını sağlamak için, sitrik asit ve stearik asit uyumlulaştırıcıları ilave edildi. Bozunmayı hızlandırmak için kobalt(II) asetilasetonat pro-oksidan olarak kullanılmıştır. Malç filmler bozunması için 180 gün Coriolus versicolor (L.) Quél ve Postia plasenta (Fr.) M.J. Larsen & Lombard ile aşılanmış topraklara gömüldü. Filmlerin kimyasal yapılarındaki değişiklikler toprağa gömülmeden önce ve sonra FTIR spektroskopisi ile değerlendirildi. Tüm örneklerin ağırlık kaybı 180 gün biyobozunmadan sonra ölçüldü ve artan nişasta içeriği ile ağırlık kaybının hızlandığı görüldü. Uyumlaştırıcıların, malç karışımların ısıl, mekanik ve morfolojik özelliklerine etkileri TGA, mekanik testler ve SEM ile belirlenmiştir. Kobalt(II)asetilasetonat sitrik asit ile birlikte kullanıldığında TPN'nın filmlerdeki ısıl kararlılığı gelişmiştir. Aynı zamanda, sitrik asit ile hazırlanan filmler stearik asit ile kıyasla kopma anında daha yüksek uzama değerleri göstermiştir. Anahtar Kelimeler AYPE, termoplastik buğday nişastası, pro-oksidan, uyumlaştırıcı. A B S T R A C T L ow density polyethylene (LDPE) is one of the most widely used plastic in agriculture and the degradability of mulch film is increased by introducing thermoplastic starch (TPS) into the LDPE. In this study, TPS/LDPE blends were prepared by twin screw compounder and TPS content is varied from 20 to 40%. To improve the interfacial adhesion and dispersion of TPS, citric acid and stearic acid were added as compatibilizers. To accelerate the degradation cobalt(II)acetylacetonate was used as a pro-oxidant. The blended mulch films were buried in soil inoculated with Coriolus versicolor (L.) Quél. and Postia placenta (Fr.) M.J. Larsen & Lombard for 180 days for the degradation. The changes in the chemical structures of the films were evaluated by FTIR spectroscopy before and after soil burial treatment. The weight loss of all samples achieved after 180 days of biodegradation and increasing starch content speeded up the weight loss. The effects of compatibilizers on thermal, tensile and morphological properties of blends were determined by TGA, mechanical and SEM analysis. When cobalt(II)acetylacetonate used together with citric acid, the thermal stability of TPS in films was enhanced. It was also found that samples with citric acid exhibited higher elongation at break values compared to films with stearic acid.

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Polymer International, 2010

and poly(DMS-block-TMSHEMA) copolymers thus obtained were characterized using Fourier transform i... more and poly(DMS-block-TMSHEMA) copolymers thus obtained were characterized using Fourier transform infrared and 1 H NMR spectroscopy and differential scanning calorimetry. After the deprotection of trimethylsilyl groups, poly(DMS-block-HEMA) and poly(DMS-block-EMA) copolymer film surfaces were analysed using scanning electron microscopy and X-ray photoelectron spectroscopy. The effects of the PDMS concentration in the copolymers on both air and glass sides of films were examined. The PDMS segments oriented and moved to the glass side in poly(DMS-block-EMA) copolymer film while orientation to the air side became evident with increasing DMS content in poly(DMS-block-HEMA) copolymer film. The block copolymerization technique described here is a versatile and economic method and is also applicable to a wide range of monomers. The copolymers obtained have phase-separated morphologies and the effects of DMS segments on copolymer film surfaces are different at the glass and air sides. Figure 4. 1 H NMR spectra of (a) PDMS, (b) PDMS-MAI, (c) poly(DMS-b-TMSHEMA) and (d) poly(DMS-b-HEMA).

Journal of Macromolecular Science, Part A, 2014

Journal of Applied Polymer Science, 2009

Journal of Applied Polymer Science, 2012

a b s t r a c t CO 2 removal from different gas streams via the polymeric membranes has been prop... more a b s t r a c t CO 2 removal from different gas streams via the polymeric membranes has been propounded as an important issue in greenhouse gas emissions control, natural gas upgrading, and enhanced oil recovery. Here, polymeric blend membranes were prepared from acrylonitrile-butadiene-styrene (ABS) and poly vinyl acetate (PVAc), and their CO 2 /N 2 and CO 2 /CH 4 separation characteristics were investigated. The influence of different PVAc contents on gas separation performance and the effect of pressure, ranging from 1 to 8 bar, on CO 2 permeability were studied. Furthermore, the morphology of the membranes was analyzed by FTIR, XRD, DSC and SEM. It was shown that the highest CO 2 permeability of 5.72 Barrer for the membrane containing 10 wt.% PVAc, the highest CO 2 /CH 4 selectivity was 29 in 20 wt.% PVAc and CO 2 /N 2 was 40.41 in 30 wt.% PVAc contents. These results comprised from different effective factors such as PVAc acetate polar groups, compactness in polymer matrix at the presence of high molecular weight PVAc, and the acrylonitrile and flexible butadiene contents of ABS. Furthermore, in the transmembrane pressure of 2-8 bar the CO 2 permeability approximately descended with the pressure increase for PVAc content of 0-40 wt.%, and it ascended for 50-60 wt.%. Generally, the prepared membranes can be taken into account as better membranes for CO 2 /N 2 separation than CO 2 /CH 4 .

Electrochimica Acta, 2014

Abstract A fluorescent pyrrole derivative bearing a dansyl substituent was prepared by a simple s... more Abstract A fluorescent pyrrole derivative bearing a dansyl substituent was prepared by a simple synthetic route and electropolymerized onto Indium Tin Oxide (ITO) electrodes. The presence of the dansyl group in the monomer precursor prevents the electropolymerization in usual systems, such as (C 4 H 9 ) 4 NBF 4 in acetonitrile (CH 3 CN). For this reason, it was added 20% boron trifluoride diethyl etherate (BFEE) to this system, to achieve electropolymerization. The resulting poly[3-( N -pyrrolyl)propyl dansylglycinate] (PPyPDG) films displayed electrochromic behavior. Their color varied from greenish-yellow, in the neutral state, to greyish-green, in the oxidized state; moreover PPyPDG is a good green light emitter material. Therefore, PPyPDG films might be potentially applicable in displays and optoelectronic devices.

Journal of Electroanalytical Chemistry

Mugla Journal of Science and Technology, 2017

The improved dispersion of clay minerals has an essential role for polymer clay nanocomposite man... more The improved dispersion of clay minerals has an essential role for polymer clay nanocomposite manufacturing. In this regard, different organomodifications of clay have been attempted to obtain intercalated/exfoliated structures of composites. In present study, Çanakkale bentonite was organically modified by four different quaternary ammonium salts: tetramethylammonium chloride (TMAC), hexadecylpyridinium chloride (HDPC), hexadecyltrimethylammonium bromide (HDAB), phenyltrimethylammonium chloride (PMAC). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis and thermogravimetric analysis (TGA) were performed to characterize the organobentonites. The results revealed that there is an increment of basal spacing of bentonite with HDAB and HDPC salts from 14.9 Å to 20.7 Å and 21.4 Å, respectively. However, other modifiers cannot lead to significant changes in d-spacings.

Az yoğunluklu polietilen (AYPE) tarımda yaygın olarak kullanılan plastiklerden biridir ve LDPE’de... more Az yoğunluklu polietilen (AYPE) tarımda yaygın olarak kullanılan plastiklerden biridir ve LDPE’den üretilen malç filmlerin bozunabilirliği termoplastik nişasta (TPN) eklenmesi ile artırılmaktadır. Bu çalışmada, bileşiminde %20’den %40’a kadar değişen oranlarda TPN bulunan TPN/LDPE karışımları çift vidalı karıştırıcı kullanılarak hazırlandı. TPN’nın ara yüzey yapışmasını geliştirmek ve matris içinde daha iyi dağılmasını sağlamak için, sitrik asit ve stearik asit uyumlulaştırıcıları ilave edildi. Bozunmayı hızlandırmak için kobalt(II) asetilasetonat pro-oksidan olarak kullanılmıştır. Malç filmler bozunması için 180 gün Coriolus versicolor (L.) Quél ve Postia plasenta (Fr.) M.J. Larsen & Lombard ile aşılanmış topraklara gömüldü. Filmlerin kimyasal yapılarındaki değişiklikler toprağa gömülmeden önce ve sonra FTIR spektroskopisi ile değerlendirildi. Tüm örneklerin ağırlık kaybı 180 gün biyobozunmadan sonra ölçüldü ve artan nişasta içeriği ile ağırlık kaybının hızlandığı görüldü. Uyumlaşt...

Materials Science and Engineering: C, 2021

In transdermal drug delivery applications uniform drug distribution and sustained release are of ... more In transdermal drug delivery applications uniform drug distribution and sustained release are of great importance to decrease the side effects. In this direction in the present research, vanillin crosslinked chitosan (CS) and polyvinyl alcohol (PVA) blend based matrix-type transdermal system was prepared by casting and drying of aqueous solutions for local delivery of enrofloxacin (ENR) drug. Subsequently, the properties including the morphology, chemical structure, thermal behavior, tensile strength, crosslinking degree, weight uniformity, thickness, swelling and drug release of the CS-PVA blend films before and after crosslinking were characterized. In vitro drug release profiles showed the sustained release of ENR by the incorporation of vanillin as a crosslinker into the CS-PVA polymer matrix. Furthermore, the release kinetic profiles revealed that the followed mechanism for all samples was Higuchi and the increase of vanillin concentration in the blend films resulted in the change of diffusion mechanism from anomalous transport to Fickian diffusion. Overall, the obtained results suggest that the investigated vanillin crosslinked CS-PVA matrix-type films are potential candidates for transdermal drug delivery system.

Journal of Electronic Materials

Conductive polymers, such as polyaniline (PANI) and polypyrrole (PPy), are widely used in the des... more Conductive polymers, such as polyaniline (PANI) and polypyrrole (PPy), are widely used in the design of supercapacitors because of their high pseudo-capacitive performance as well as facile synthesis and low cost. In this study, hybrid aerogels based on reduced graphene oxide and ZnMn2O4 were modified by PANI and PPy. The 3D structure of the hybrid aerogels was obtained by using a one-step hydrothermal co-assembly method. Then, aniline and pyrrole were polymerized on and within the structure of the hybrid aerogel through in situ polymerization. The electrochemical properties of the hybrid aerogels were studied via cyclic voltammetry and galvanostatic charge–discharge testing to identify the effects of conductive polymers on the electrochemical properties of materials. It has been established that PANI and PPy facilitate an increase of the specific capacitance of rGO/ZnMn2O4 aerogels up to 297.8 F/g and 108.24 F/g at 0.2 A/g scan rate, respectively.

International Journal of Polymeric Materials and Polymeric Biomaterials

Nanomaterials

To improve Li storage capacity and the structural stability of Ti3C2 MXene-based electrode materi... more To improve Li storage capacity and the structural stability of Ti3C2 MXene-based electrode materials for lithium-ion batteries (LIBs), a facile strategy is developed to construct three-dimensional (3D) hierarchical porous Ti3C2/bimetal-organic framework (NiCo-MOF) nanoarchitectures as anodes for high-performance LIBs. 2D Ti3C2 nanosheets are coupled with NiCo-MOF nanoflakes induced by hydrogen bonds to form 3D Ti3C2/NiCo-MOF composite films through vacuum-assisted filtration technology. The morphology and electrochemical properties of Ti3C2/NiCo-MOF are influenced by the mass ratio of MOF to Ti3C2. Owing to the interconnected porous structures with a high specific surface area, rapid charge transfer process, and Li+ diffusion rate, the Ti3C2/NiCo-MOF-0.4 electrode delivers a high reversible capacity of 402 mAh g−1 at 0.1 A g−1 after 300 cycles; excellent rate performance (256 mAh g−1 at 1 A g−1); and long-term stability with a capacity retention of 85.7% even after 400 cycles at a h...

Journal of Applied Polymer Science

Maderas. Ciencia y tecnología

This study investigated the thermal properties of Oriental beech (Fagus orientalis) treated with ... more This study investigated the thermal properties of Oriental beech (Fagus orientalis) treated with (NH 4) 2 H-PO 4 , K 2 HPO 4 , NH 4 Cl and (NH 4) 2 SO 4 salts and their mixtures (1:1; w/w) aqueous solutions at 3% concentrations. The effects of different inorganic salts fire retardants on the thermal degradation characteristics of wood samples were evaluated by thermogravimetric analysis (TGA). Based on the TGA curve for untreated beech wood, weight loss takes place at three distinct steps. The impregnation of inorganic salts resulted in higher char yields and additional thermal degradation steps were identified. The highest char yield (80%) was obtained from (NH 4) 2 HPO 4-K 2 HPO 4 mixture impregnated sample. Salt mixtures containing phosphates ((NH 4) 2 HPO 4 and K 2 HPO 4) have remarkable effects on thermal stability of beech wood, whereas NH 4 Cl salt lowered the decomposition temperatures and char yield.

Journal of Macromolecular Science Pure and Applied Chemistry, Jul 30, 2010

ABSTRACT The degradation of poly(hydroxyethyl methacrylate), PHEMA obtained by γ -radiation induc... more ABSTRACT The degradation of poly(hydroxyethyl methacrylate), PHEMA obtained by γ -radiation induced polymerization of HEMA in aqueous solution, was studied. The polymer was a gel type and insoluble in common organic solvents. The DSC thermogram of the polymer gave a Tg value at 88.2°C and an endothermic peak showed further polymerization or crosslinking at 110–160°C. The degradation observed in TGA was a depolymerization type. However, the FT-IR of TGA fragments showed no monomer, which was degraded further. The degradation of monomer was studied by the GC-MS method. Similar results were also observed.

Hacettepe Journal of Biology and Chemistry

K ısmen bozunabilen malç filmleri hazırlamak için az yoğunluklu polietilen (AYPE), termoplastik n... more K ısmen bozunabilen malç filmleri hazırlamak için az yoğunluklu polietilen (AYPE), termoplastik nişasta (TPN) ile çift vidalı ekstruder yardımıyla karıştırıldı. Bu çalışmada, demir(III) stearat ve manganez(II) stearat pro-oksidan olarak kullanılmışve farklı pro-oksidanların karışımların bozunması üzerindeki etkisi incelenmiştir. Malç filmler Coriolus versicolor (L.) Quel ile aşılanmış toprağa gömülerek 180 gün boyunca degrede edilmiştir. Filmlerin kimyasal yapıları FTIR spektroskopisi ile belirlenmiş ve tüm numunelerin ağırlık kaybı toprakta bozunma öncesi ve sonrası ölçülmüştür. İki farklı pro-oksidanın, malç karışımların ısıl ve germe özellikleri üzerine etkisi TGA ve mekanik analiz ile tespit edilmiştir. Demir (III) stearat ve sitrik asitin birlikte kullanılmasıyla sinerjik bir etki gözlenmiştir. Her ikisinin birlikte kullanıldığı karışımlarda TPN'nin yüksek ısıl kararlılık gösterdiği bulunmuştur. Ayrıca, mekanik özelliklerinde belirgin düzelme gözlenmiştir. Bununla birlikte, manganez(II) stearat sitrik asit ile birlikte kullanıldığında stearik asitli karışımlarına kıyasla daha zayıf mekanik özellikler göstermiştir. Anahtar Kelimeler AYPE, termoplastik nişasta, pro-oksidan, demir stearat, manganez(II) stearat.

A z yoğunluklu polietilen (AYPE) tarımda yaygın olarak kullanılan plastiklerden biridir ve LDPE'd... more A z yoğunluklu polietilen (AYPE) tarımda yaygın olarak kullanılan plastiklerden biridir ve LDPE'den üretilen malç filmlerin bozunabilirliği termoplastik nişasta (TPN) eklenmesi ile artırılmaktadır. Bu çalışmada, bileşiminde %20'den %40'a kadar değişen oranlarda TPN bulunan TPN/LDPE karışımları çift vidalı karıştırıcı kullanılarak hazırlandı. TPN'nın ara yüzey yapışmasını geliştirmek ve matris içinde daha iyi dağılmasını sağlamak için, sitrik asit ve stearik asit uyumlulaştırıcıları ilave edildi. Bozunmayı hızlandırmak için kobalt(II) asetilasetonat pro-oksidan olarak kullanılmıştır. Malç filmler bozunması için 180 gün Coriolus versicolor (L.) Quél ve Postia plasenta (Fr.) M.J. Larsen & Lombard ile aşılanmış topraklara gömüldü. Filmlerin kimyasal yapılarındaki değişiklikler toprağa gömülmeden önce ve sonra FTIR spektroskopisi ile değerlendirildi. Tüm örneklerin ağırlık kaybı 180 gün biyobozunmadan sonra ölçüldü ve artan nişasta içeriği ile ağırlık kaybının hızlandığı görüldü. Uyumlaştırıcıların, malç karışımların ısıl, mekanik ve morfolojik özelliklerine etkileri TGA, mekanik testler ve SEM ile belirlenmiştir. Kobalt(II)asetilasetonat sitrik asit ile birlikte kullanıldığında TPN'nın filmlerdeki ısıl kararlılığı gelişmiştir. Aynı zamanda, sitrik asit ile hazırlanan filmler stearik asit ile kıyasla kopma anında daha yüksek uzama değerleri göstermiştir. Anahtar Kelimeler AYPE, termoplastik buğday nişastası, pro-oksidan, uyumlaştırıcı. A B S T R A C T L ow density polyethylene (LDPE) is one of the most widely used plastic in agriculture and the degradability of mulch film is increased by introducing thermoplastic starch (TPS) into the LDPE. In this study, TPS/LDPE blends were prepared by twin screw compounder and TPS content is varied from 20 to 40%. To improve the interfacial adhesion and dispersion of TPS, citric acid and stearic acid were added as compatibilizers. To accelerate the degradation cobalt(II)acetylacetonate was used as a pro-oxidant. The blended mulch films were buried in soil inoculated with Coriolus versicolor (L.) Quél. and Postia placenta (Fr.) M.J. Larsen & Lombard for 180 days for the degradation. The changes in the chemical structures of the films were evaluated by FTIR spectroscopy before and after soil burial treatment. The weight loss of all samples achieved after 180 days of biodegradation and increasing starch content speeded up the weight loss. The effects of compatibilizers on thermal, tensile and morphological properties of blends were determined by TGA, mechanical and SEM analysis. When cobalt(II)acetylacetonate used together with citric acid, the thermal stability of TPS in films was enhanced. It was also found that samples with citric acid exhibited higher elongation at break values compared to films with stearic acid.

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Polymer International, 2010

and poly(DMS-block-TMSHEMA) copolymers thus obtained were characterized using Fourier transform i... more and poly(DMS-block-TMSHEMA) copolymers thus obtained were characterized using Fourier transform infrared and 1 H NMR spectroscopy and differential scanning calorimetry. After the deprotection of trimethylsilyl groups, poly(DMS-block-HEMA) and poly(DMS-block-EMA) copolymer film surfaces were analysed using scanning electron microscopy and X-ray photoelectron spectroscopy. The effects of the PDMS concentration in the copolymers on both air and glass sides of films were examined. The PDMS segments oriented and moved to the glass side in poly(DMS-block-EMA) copolymer film while orientation to the air side became evident with increasing DMS content in poly(DMS-block-HEMA) copolymer film. The block copolymerization technique described here is a versatile and economic method and is also applicable to a wide range of monomers. The copolymers obtained have phase-separated morphologies and the effects of DMS segments on copolymer film surfaces are different at the glass and air sides. Figure 4. 1 H NMR spectra of (a) PDMS, (b) PDMS-MAI, (c) poly(DMS-b-TMSHEMA) and (d) poly(DMS-b-HEMA).

Journal of Macromolecular Science, Part A, 2014

Journal of Applied Polymer Science, 2009

Journal of Applied Polymer Science, 2012

a b s t r a c t CO 2 removal from different gas streams via the polymeric membranes has been prop... more a b s t r a c t CO 2 removal from different gas streams via the polymeric membranes has been propounded as an important issue in greenhouse gas emissions control, natural gas upgrading, and enhanced oil recovery. Here, polymeric blend membranes were prepared from acrylonitrile-butadiene-styrene (ABS) and poly vinyl acetate (PVAc), and their CO 2 /N 2 and CO 2 /CH 4 separation characteristics were investigated. The influence of different PVAc contents on gas separation performance and the effect of pressure, ranging from 1 to 8 bar, on CO 2 permeability were studied. Furthermore, the morphology of the membranes was analyzed by FTIR, XRD, DSC and SEM. It was shown that the highest CO 2 permeability of 5.72 Barrer for the membrane containing 10 wt.% PVAc, the highest CO 2 /CH 4 selectivity was 29 in 20 wt.% PVAc and CO 2 /N 2 was 40.41 in 30 wt.% PVAc contents. These results comprised from different effective factors such as PVAc acetate polar groups, compactness in polymer matrix at the presence of high molecular weight PVAc, and the acrylonitrile and flexible butadiene contents of ABS. Furthermore, in the transmembrane pressure of 2-8 bar the CO 2 permeability approximately descended with the pressure increase for PVAc content of 0-40 wt.%, and it ascended for 50-60 wt.%. Generally, the prepared membranes can be taken into account as better membranes for CO 2 /N 2 separation than CO 2 /CH 4 .