Fiber-reinforced polymer composites occupy a fair share of structural and lightweight applications, replacing traditional materials whenever possible. Along with many advantages they offer, such as excellent mechanical properties to weight ratio, low price, fast production, the possibility of tailoring the properties for specific applications, etc. On the other hand, at the end of their lifetime, they are usually disposed of in landfills. Carbon fiber polymer composites (CFRPs) are relatively expensive materials and should be considered for recycling and reuse. Therefore, the influence of multiple cycles of mechanical recycling through grinding and injection molding was studied. PA66, PA66 reinforced with CF, and ground CF were mechanically recycled five times. Mechanical and thermal properties were determined after the first injection, as well as after the 1st, 3rd and 5th cycle of mechanical recycling. The values of mechanical properties (modulus, strength, ...) generally deteriorate, while the thermal properties remain almost unchanged. Part of the change is due to polymer degradation and part is due to fiber shortening.
{"title":"MECHANICAL RECYCLING OF SHORT CARBON FIBERS AND GROUND CARBON FIBERS REINFORCED PA66","authors":"Rebeka Lorber, M. Huskić, B. Nardin","doi":"10.7251/comen2201055l","DOIUrl":"https://doi.org/10.7251/comen2201055l","url":null,"abstract":"Fiber-reinforced polymer composites occupy a fair share of structural and lightweight applications, replacing traditional materials whenever possible. Along with many advantages they offer, such as excellent mechanical properties to weight ratio, low price, fast production, the possibility of tailoring the properties for specific applications, etc. On the other hand, at the end of their lifetime, they are usually disposed of in landfills. Carbon fiber polymer composites (CFRPs) are relatively expensive materials and should be considered for recycling and reuse. Therefore, the influence of multiple cycles of mechanical recycling through grinding and injection molding was studied. PA66, PA66 reinforced with CF, and ground CF were mechanically recycled five times. Mechanical and thermal properties were determined after the first injection, as well as after the 1st, 3rd and 5th cycle of mechanical recycling. The values of mechanical properties (modulus, strength, ...) generally deteriorate, while the thermal properties remain almost unchanged. Part of the change is due to polymer degradation and part is due to fiber shortening.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82792544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Apostolov, Borko M. Matijević, Gorana S. Mrđan, Đ. Vaštag
In silico approach is increasingly used in modern design to establish the qualitative / quantitative dependence between structure, physico-chemical properties and biological activity of the new molecule. The selection and application of appropriate molecular descriptors are important step in this process. Given the presence of the amide group in numerous pharmacologically and biologically active molecules, in the pharmaceutical and chemical industries its formation represents an eternal challenge and a significant transformation in the design of the synthetic plan. Evaluation of the biological potential of selected amide derivatives included theoretical and experimental determination of their lipophilicity, analysis of their bioavailability, study of their pharmacokinetic predictors and ecotoxicity parameters. The parameters (RM0, m and C0) obtained by applying reversed-phase thin layer chromatography (RP TLC18 F254s) in the presence of two organic modifiers, as assumed measures of lipophilicity of the examined amide derivatives were correlated with the studied parameters of biological activity by the linear regression method. The quality of the obtained mathematical models was confirmed by the values of statistical validation parameters.
{"title":"APPLICATION OF THE CHROMATOGRAPHIC PARAMETERS IN THE ASSESSMENT OF AMIDE DERIVATIVES’ BIOLOGICAL POTENTIAL","authors":"S. Apostolov, Borko M. Matijević, Gorana S. Mrđan, Đ. Vaštag","doi":"10.7251/comen2101057a","DOIUrl":"https://doi.org/10.7251/comen2101057a","url":null,"abstract":"In silico approach is increasingly used in modern design to establish the qualitative / quantitative dependence between structure, physico-chemical properties and biological activity of the new molecule. The selection and application of appropriate molecular descriptors are important step in this process. Given the presence of the amide group in numerous pharmacologically and biologically active molecules, in the pharmaceutical and chemical industries its formation represents an eternal challenge and a significant transformation in the design of the synthetic plan. Evaluation of the biological potential of selected amide derivatives included theoretical and experimental determination of their lipophilicity, analysis of their bioavailability, study of their pharmacokinetic predictors and ecotoxicity parameters. The parameters (RM0, m and C0) obtained by applying reversed-phase thin layer chromatography (RP TLC18 F254s) in the presence of two organic modifiers, as assumed measures of lipophilicity of the examined amide derivatives were correlated with the studied parameters of biological activity by the linear regression method. The quality of the obtained mathematical models was confirmed by the values of statistical validation parameters.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78422979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Janja Todorović, M. Saletović, Dijana Mihajlović, D. Gajić, D. Blagojević, Dijana Jelić
Pyrophyllite clay, modified with PVP coated silver nanoparticles (PYRO-PVP/AgNPs), with recently proved antibacterial activity was prepared. Silver nanoparticles were synthesized by the chemical reduction method of AgNO3 using NaBH4 and poly(vinyl pyrrolidone) (PVP) as a stabilizer and excellent dispersant. This research aimed to elucidate the mechanisms and kinetics of AgNPs, along with the PVP protective mechanism responsible for antibacterial activity towards the microorganisms. Pioneering steps were made toward coagulation studies due to the potential of aluminosilicate layered clays to serve as alternatives to hemostatic agents currently in use. The isoelectric point of pyrophyllite samples with 5, 20, and 45 μm diameter particles and PYRO/PVP/AgNPs sample (Ag25mg/L) was evaluated to understand how the anticoagulant or procoagulant properties of the pyrophyllite varied according to the pH of the isoelectric point. Characterization of the PYRO-PVP/AgNPs samples was performed using FTIR spectroscopy, while the release mechanism and kinetics of silver ions were monitored using atomic absorption spectroscopy (AAS). Additionally, AAS was used for the evaluation of heavy metals content in pyrophyllite clay and a simple, cost-effective procedure was proposed for the extraction of heavy metals.
{"title":"DEVELOPMENT OF LONG-LASTING ANTIMICROBIAL AND POTENTIAL HEMOSTATIC NANOCOMPOSITES (pyrophyllite based) WITH PVP-coated COLLOIDAL SILVER NANOPARTICLES","authors":"Janja Todorović, M. Saletović, Dijana Mihajlović, D. Gajić, D. Blagojević, Dijana Jelić","doi":"10.7251/comen2201092t","DOIUrl":"https://doi.org/10.7251/comen2201092t","url":null,"abstract":"Pyrophyllite clay, modified with PVP coated silver nanoparticles (PYRO-PVP/AgNPs), with recently proved antibacterial activity was prepared. Silver nanoparticles were synthesized by the chemical reduction method of AgNO3 using NaBH4 and poly(vinyl pyrrolidone) (PVP) as a stabilizer and excellent dispersant. This research aimed to elucidate the mechanisms and kinetics of AgNPs, along with the PVP protective mechanism responsible for antibacterial activity towards the microorganisms. Pioneering steps were made toward coagulation studies due to the potential of aluminosilicate layered clays to serve as alternatives to hemostatic agents currently in use. The isoelectric point of pyrophyllite samples with 5, 20, and 45 μm diameter particles and PYRO/PVP/AgNPs sample (Ag25mg/L) was evaluated to understand how the anticoagulant or procoagulant properties of the pyrophyllite varied according to the pH of the isoelectric point. Characterization of the PYRO-PVP/AgNPs samples was performed using FTIR spectroscopy, while the release mechanism and kinetics of silver ions were monitored using atomic absorption spectroscopy (AAS). Additionally, AAS was used for the evaluation of heavy metals content in pyrophyllite clay and a simple, cost-effective procedure was proposed for the extraction of heavy metals.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"278 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83429052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dispersion and settling behavior of goethite has been studied and effect of pH values on surface properties of goethite particles with /without dispersants has been discussed. A prerequisite for the successful flocculation is the stabilization of the system which is achieved by the good dispersion of particles. The effect of pH, sodium silicate (Na2SiO3), sodium hexametaphosphate (Na6P6O18) and sodium pyrophosphate (Na4P2O7), on the surface charges of goethite was studied. The IEP of natural goethite was found by measuring zeta potential at pH value of 6.6. With the use of sodium silicate the IEP of goethite moves to pH 4.95. An IEP could not be detected when the poly-phosphates were used and the surface charge is negative from pH 2 to pH 12. The relatively high zeta potential values indicate a fairly stable dispersion, especially when the sodium hexametaphosphate were used as dispersant.
{"title":"EFFECT OF PH CONDITIONS ON GOETHITE BEHAVIOR IN THE PRESENCE/ABSENCE OF DIFFERENT DISPERSANTS","authors":"S. Sredić, Ljiljana Tankosić","doi":"10.7251/comen2101091s","DOIUrl":"https://doi.org/10.7251/comen2101091s","url":null,"abstract":"Dispersion and settling behavior of goethite has been studied and effect of pH values on surface properties of goethite particles with /without dispersants has been discussed. A prerequisite for the successful flocculation is the stabilization of the system which is achieved by the good dispersion of particles. The effect of pH, sodium silicate (Na2SiO3), sodium hexametaphosphate (Na6P6O18) and sodium pyrophosphate (Na4P2O7), on the surface charges of goethite was studied. The IEP of natural goethite was found by measuring zeta potential at pH value of 6.6. With the use of sodium silicate the IEP of goethite moves to pH 4.95. An IEP could not be detected when the poly-phosphates were used and the surface charge is negative from pH 2 to pH 12. The relatively high zeta potential values indicate a fairly stable dispersion, especially when the sodium hexametaphosphate were used as dispersant.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84116105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Pavlovic, D. Mirjanić, I. Radonjić, L. Pantić, Galina I. Sazhko
The paper presents an atlas of solar radiation for the city of Banja Luka in the Republic of Srpska formed by PVGIS estimation utility. The atlas contains the results of calculating global and direct solar radiation falling on the horizontal surface and global solar radiation falling on the optimally placed surface in Banja Luka in the period from 2007 to 2016. In addition, the intensity of global, direct and diffuse solar radiation falling on the optimally placed surface in Banja Luka is given by months. It was found that 13.89% less solar radiation falls on the horizontal surface and 47.31% less on the vertical surface as compared to the solar radiation that falls on the optimally placed surface. The basic characteristics of fixed, one-axis and dual-axis tracking PV solar power plants power of 1 MWp and the amount of electricity that can be generated by them in Banja Luka, are also given. It was found that with the one-axis tracking solar power plant 30.18% more electricity can be generated, and with the dual-axis tracking solar power plant 33.37% more electricity can be generated as compared to the fixed solar power plant.
{"title":"SOLAR RADIATION ATLAS IN BANJA LUKA IN THE REPUBLIC OF SRPSKA","authors":"T. Pavlovic, D. Mirjanić, I. Radonjić, L. Pantić, Galina I. Sazhko","doi":"10.7251/comen2101039m","DOIUrl":"https://doi.org/10.7251/comen2101039m","url":null,"abstract":"The paper presents an atlas of solar radiation for the city of Banja Luka in the Republic of Srpska formed by PVGIS estimation utility. The atlas contains the results of calculating global and direct solar radiation falling on the horizontal surface and global solar radiation falling on the optimally placed surface in Banja Luka in the period from 2007 to 2016. In addition, the intensity of global, direct and diffuse solar radiation falling on the optimally placed surface in Banja Luka is given by months. It was found that 13.89% less solar radiation falls on the horizontal surface and 47.31% less on the vertical surface as compared to the solar radiation that falls on the optimally placed surface. The basic characteristics of fixed, one-axis and dual-axis tracking PV solar power plants power of 1 MWp and the amount of electricity that can be generated by them in Banja Luka, are also given. It was found that with the one-axis tracking solar power plant 30.18% more electricity can be generated, and with the dual-axis tracking solar power plant 33.37% more electricity can be generated as compared to the fixed solar power plant.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74119372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Saša Zeljković, Mladena Malinović, Sunčica Sukur, D. Gajić, Milica Balaban, G. Ostojic
Lanthanum(III)-oxide (La2O3) powders were synthesized by a mechanochemically induced solvent-deficient method using lanthanum nitrate, and ammonium bicarbonate as precursors. The precursor mixture was calcined for one hour at either 600 or 800 °C. This study included an investigation of the formation reactions, crystal structure, specific surface area, and optical properties of synthesized La2O3. The proposed mechanism indicates a complex synthesis with several reactions, some of which are mechanochemically induced. The size of the La2O3 nanocrystallites, as determined by XRD, is 22.15±3.9 nm (by using the Williamson-Hall plot, it is determined that the strain is 1.4×10−3 and crystallite size 30.81 nm) while the specific surface is set to 7.04 m2g-1. The direct bandgap value obtained from reflectance measurement is determined to be 5.37 eV.
{"title":"MECHANOCHEMICALLY INDUCED SYNTHESIS OF La2O3","authors":"Saša Zeljković, Mladena Malinović, Sunčica Sukur, D. Gajić, Milica Balaban, G. Ostojic","doi":"10.7251/comen2201045z","DOIUrl":"https://doi.org/10.7251/comen2201045z","url":null,"abstract":"Lanthanum(III)-oxide (La2O3) powders were synthesized by a mechanochemically induced solvent-deficient method using lanthanum nitrate, and ammonium bicarbonate as precursors. The precursor mixture was calcined for one hour at either 600 or 800 °C. This study included an investigation of the formation reactions, crystal structure, specific surface area, and optical properties of synthesized La2O3. The proposed mechanism indicates a complex synthesis with several reactions, some of which are mechanochemically induced. The size of the La2O3 nanocrystallites, as determined by XRD, is 22.15±3.9 nm (by using the Williamson-Hall plot, it is determined that the strain is 1.4×10−3 and crystallite size 30.81 nm) while the specific surface is set to 7.04 m2g-1. The direct bandgap value obtained from reflectance measurement is determined to be 5.37 eV.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82463165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The subject of this paper is interdisciplinary research on resource management based on a sustainable method for the prediction of the availability of resources. The method is developed and tested in the water resources case study because water is one of the most important substances on the planet. The motivation for this research lies in numerous conflicting interests regarding different resource usage. In the case of water use, conflicting interests are especially highlighted due to a deteriorated environment, deficiency of water, deficiency of data and deficiency of proper methodologies for sustainable solutions. Different researches are done using artificial intelligence applications to analyze various models of water management optimization in conditions of conflicting interests relating to water use. This research aims to interdisciplinary investigate water management methods from the aspect of sustainability, under the condition of incomplete and uncertain information. This paper analyses the model for predicting the availability of water resources from the aspect of different impacts.
{"title":"INTERDISCIPLINARY RESEARCH ON RESOURCES MANAGEMENT BASED ON THE SUSTAINABLE PREDICTION METHOD","authors":"Ivan Stevović, Z. Kapelan, V. Obradović","doi":"10.7251/comen2201028s","DOIUrl":"https://doi.org/10.7251/comen2201028s","url":null,"abstract":"The subject of this paper is interdisciplinary research on resource management based on a sustainable method for the prediction of the availability of resources. The method is developed and tested in the water resources case study because water is one of the most important substances on the planet. The motivation for this research lies in numerous conflicting interests regarding different resource usage. In the case of water use, conflicting interests are especially highlighted due to a deteriorated environment, deficiency of water, deficiency of data and deficiency of proper methodologies for sustainable solutions. Different researches are done using artificial intelligence applications to analyze various models of water management optimization in conditions of conflicting interests relating to water use. This research aims to interdisciplinary investigate water management methods from the aspect of sustainability, under the condition of incomplete and uncertain information. This paper analyses the model for predicting the availability of water resources from the aspect of different impacts.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"29 3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77483524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Djunakova, B. Kunovska, N. Chobanova, J. Djounova, K. Ivanova, Z. Stojanovska
The objective of this study was to evaluate the indoor gamma dose rate in 17 inspected hospitals for rehabilitation where the radon measurements were conducted and to give a more comprehensive evaluation of the total exposure dose. The gamma dose rate in the air was measured in 355 rooms in 17 inspected hospitals for rehabilitation on the territory of Bulgaria. The maximum parameter value was 0.390 μSv/h and the minimum value was 0.06 μSv/h with the 0.157 μSv/h arithmetic mean (standard deviation - 0.160). The gamma dose rate was within the natural variations of the parameter in buildings. Direct measurements of radon were conducted, and the results ranged from 12 Bq/m3 to 3920 Bq/m3. The relationship between the two parameters was examined. A weak correlation between gamma dose rate and indoor radon concentration was found. The measurement of a gamma dose rate could be a useful parameter for carrying out radon workplace control.
{"title":"MEASUREMENT OF GAMMA DOSE RATE IN HOSPITALS FOR REHABILITATION IN BULGARIA","authors":"D. Djunakova, B. Kunovska, N. Chobanova, J. Djounova, K. Ivanova, Z. Stojanovska","doi":"10.7251/comen2101026d","DOIUrl":"https://doi.org/10.7251/comen2101026d","url":null,"abstract":"The objective of this study was to evaluate the indoor gamma dose rate in 17 inspected hospitals for rehabilitation where the radon measurements were conducted and to give a more comprehensive evaluation of the total exposure dose. The gamma dose rate in the air was measured in 355 rooms in 17 inspected hospitals for rehabilitation on the territory of Bulgaria. The maximum parameter value was 0.390 μSv/h and the minimum value was 0.06 μSv/h with the 0.157 μSv/h arithmetic mean (standard deviation - 0.160). The gamma dose rate was within the natural variations of the parameter in buildings. Direct measurements of radon were conducted, and the results ranged from 12 Bq/m3 to 3920 Bq/m3. The relationship between the two parameters was examined. A weak correlation between gamma dose rate and indoor radon concentration was found. The measurement of a gamma dose rate could be a useful parameter for carrying out radon workplace control.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77944204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Radanović, Ljiljana S. Vojinović-Ješić, M. Rodić, V. Leovac
Schiff bases represent an interesting class of compounds due to a wide range of possible applications, especially their biological activity. Having in mind that the biological activity of the ligand could be closely related to its coordinating properties, we examined the synthesis and structure of a novel Fe(III) complex with the Schiff base of aminoguanidine and 2-acetylpyridine. Bis(ligand) complex of iron(III), of the formula [Fe(L–H)2]2(NCS)Cl, was obtained by the reaction of FeCl3 and the thiocyanate ligand salt in a mole ratio 1:1 in the presence of lithium-acetate as a deprotonating agent. The complex is obtained in the form of brown single crystals and is characterized by elemental analysis data, conductometric measurements, IR spectra, and X-ray analysis. The latter revealed that the chelating ligand is coordinated in its monoanionic form via pyridine, azomethine, and nitrogen atoms of the aminoguanidine fragment, forming octahedral environment.
{"title":"SYNTHESIS AND STRUCTURE OF IRON(III) COMPLEX WITH 2-ACETYLPYRIDINE-AMINOGUANIDINE","authors":"M. Radanović, Ljiljana S. Vojinović-Ješić, M. Rodić, V. Leovac","doi":"10.7251/comen2101064r","DOIUrl":"https://doi.org/10.7251/comen2101064r","url":null,"abstract":"Schiff bases represent an interesting class of compounds due to a wide range of possible applications, especially their biological activity. Having in mind that the biological activity of the ligand could be closely related to its coordinating properties, we examined the synthesis and structure of a novel Fe(III) complex with the Schiff base of aminoguanidine and 2-acetylpyridine. Bis(ligand) complex of iron(III), of the formula [Fe(L–H)2]2(NCS)Cl, was obtained by the reaction of FeCl3 and the thiocyanate ligand salt in a mole ratio 1:1 in the presence of lithium-acetate as a deprotonating agent. The complex is obtained in the form of brown single crystals and is characterized by elemental analysis data, conductometric measurements, IR spectra, and X-ray analysis. The latter revealed that the chelating ligand is coordinated in its monoanionic form via pyridine, azomethine, and nitrogen atoms of the aminoguanidine fragment, forming octahedral environment.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82945447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Stojanović, Aleksandra Janićijević, A. Janićijević
Thermally prompted dehydration of binuclear [Ni2(en)2(H2O)6(pyr)]·4H2O complex occurs within a 326 K to 410 K temperature region, presenting an asymmetrical DSC peak. The process is endothermal and results in the loss of 10 molecules of water accounting for 26.8% of the total mass of the sample. Values of the apparent activation energy of 71 kJ/mol and 93 kJ/mol were determined by using Kissinger's and the isoconversional KAS approach, respectively. The probable reaction mechanism was determined by Dollimore's analysis. Deconvolution of the experimental DSC peak on different heating rates shows that the mechanism of dehydration changes with the change in the heating regime. Using the linear compensation effect, values of invariant activation energy of 61 kJ/mol as well as of Arrhenius pre-exponential factor of 6·107 min-1 were determined.
{"title":"THERMALLY GUIDED DEHYDRATION OF BINUCLEAR [Ni2(en)2(H2O)6(pyr)]·4H2O COMPLEX: A FURTHER INSIGHT","authors":"N. Stojanović, Aleksandra Janićijević, A. Janićijević","doi":"10.7251/comen2201084s","DOIUrl":"https://doi.org/10.7251/comen2201084s","url":null,"abstract":"Thermally prompted dehydration of binuclear [Ni2(en)2(H2O)6(pyr)]·4H2O complex occurs within a 326 K to 410 K temperature region, presenting an asymmetrical DSC peak. The process is endothermal and results in the loss of 10 molecules of water accounting for 26.8% of the total mass of the sample. Values of the apparent activation energy of 71 kJ/mol and 93 kJ/mol were determined by using Kissinger's and the isoconversional KAS approach, respectively. The probable reaction mechanism was determined by Dollimore's analysis. Deconvolution of the experimental DSC peak on different heating rates shows that the mechanism of dehydration changes with the change in the heating regime. Using the linear compensation effect, values of invariant activation energy of 61 kJ/mol as well as of Arrhenius pre-exponential factor of 6·107 min-1 were determined.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90816560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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