ABSTRACT The interest to innovative products with high added values and processes in textile fiel... more ABSTRACT The interest to innovative products with high added values and processes in textile field has been rapidly increasing among the other industrial fields. One of innovations in this field is to produce of innovative textiles containing phase change material (PCMs) that have thermal storage and thermo-regulation properties. This study deals with preparation and characterization of poly(methylmethacrylate-co-glycidyl methacrylate)/n-hexadecane nanocapsules containing nhexadecane as phase change material for thermal energy storage. The chemical characterization of poly(methylmethacrylateco-glycidyl methacrylate)/n-hexadecane nanocapsules was made by fourier transform infrared (FT-IR) spectroscopy method as particle size and its distribution (PSD) were studied by scanning electron microscopy (SEM). Thermal properties of nanoencapsulated n-hexadecane were determined using differential scanning calorimetry (DSC). The melting and freezing temperatures of the nanoencapsulated n-hexadecane were 17.23 and 14.85 °C respectively as the latent heats of melting and crystallization were 148.05 and −147.63 J/g respectively. Produced nanocapsules were applied to polyacrylonitrile (PAN) by means of electrospinning and surface morphology of the fibers was investigated by SEM analysis. Based on the results, it can be considered that the nanoencapsulated n-hexadecane in poly(methylmethacrylate-co-glycidyl methacrylate) have good energy storage potential to be used in fibers. KeywordsPCM–Smart textiles–Thermal comfort–Thermal energy storage
International Journal of Energy Research, Apr 1, 2020
Polymeric solid‐solid phase change materials (S‐SPCMs) are functional materials with phase transi... more Polymeric solid‐solid phase change materials (S‐SPCMs) are functional materials with phase transition‐heat storing/releasing ability. With this respect, a series of polyethylene glycol (PEG) grafted styrenic copolymer were produced as novel S‐SPCMs. PEGs with three different molecular weights were used for synthesis of isocyanate‐terminated polymers (ITPs). To achieve cross‐linking S‐SPCMs, the ITPs were grafted with styrene‐co‐ally alcohol) (PSAA) at three different PSAA:PEG mole ratios. The produced polymers were characterized using Fourier transform infrared (FT‐IR), proton nuclear magnetic resonance (1H NMR), and X‐ray diffraction (XRD) technique. The crystalline‐amorphous phase transitions of the polymers were examined using polarized optical microscopy (POM). The FT‐IR, NMR, and XRD results confirmed the expected chemical structures and crystallization performances of the polymers. Thermal energy storage (TES) properties of the S‐SPCMs were determined by differential scanning calorimetry (DSC). The DSC results revealed that the polymers with grafting ratio of PSAA:PEG(1:1) had phase transition enthalpies between about 74 and 142 J/g and phase transition temperatures between about 26°C and 57°C. Thermogravimetric analysis (TGA) measurements demonstrated that the S‐SPCMs were resistant to thermal decomposition until about 300°C. Thermal conductivities of the produced S‐SPCMs were measured in a range of about 0.18 to 0.19 W/mK. Furthermore, TES properties of the S‐SPCMs were slightly changed as their chemical structures were remained after 5000 thermal cycles. By overall evaluation of the findings, it can be foreseen that particularly PSAA‐g‐PEG(1:1) polymers can be considered as promising S‐SPCMs for some TES practices such as air conditioning of buildings, thermoregulation of food packages, automobile components, electronic devices, and solar photovoltaic panels.
In this study, the synthesis of new polymer-protein conjugates using a grafting-from strategy was... more In this study, the synthesis of new polymer-protein conjugates using a grafting-from strategy was performed by employing photo-induced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. D-aminoacylase is an industrially significant enzyme for the preparation of chiral amino acids and it is coupled with reversible addition-fragmentation (RAFT) chain transfer agent (CTA) using-activated ester chemistry. The effects of polymeric side chain compositions on the activity of D-aminoacylase were studied with two different polymeric side chain lengths. For this reason, two monomers, a hydrophilic N-(2-aminoethyl acrylamide) and a hydrophobic and N-(iso-butoxymethyl) acrylamide were used, respectively. It was found that modification by grafting from strategy increased the thermal stability of the D-aminoacylase enzyme. Additionally, the hydrophobic monomer conjugate has been reported to increase the activity of the enzyme more than the hydrophilic monomer.
Abstract Three component thermochromic dyes including fluoran type leuco dye, n-tetradecanol, and... more Abstract Three component thermochromic dyes including fluoran type leuco dye, n-tetradecanol, and phenolphthaleinwere prepared and encapsulated in polymethylmethacrylate in this study. Nanoencapsulated system was prepared via oil in water emulsion polymerization technique. According to the morphological investigation by SEM, nanocapsules having spherical shape, compact morphology and lower average diameter around 200 nm were prepared successfully. UV–Visible Spectroscopy analysis and the photographs taken by a digital camera indicated that thermochromic systems and their nanocapsules exhibited reversible color change with thermal stimuli. They were green color at room temperature and lost their color at temperatures upon melting point of the thermochromic systems. In the study, 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone were added to the thermochromic systems to investigate UV resistance of the colorants in the systems. The effect of the UV absorbers on UV resistance of the thermochromic systems was investigated by color measurements based on CIELab system after UV aging of the nanoencapsulated systems. The results proved that especially 2,4-dihydroxybenzophenone was an effective material for increasing UV resistance of the systems and had color developer property. Besides, both thermochromic systems and their nanoencapsulated derivatives exhibited thermal energy storage/releasing property. While thermochromic systems had a heat storage capacity of over 200 J/g, the heat storage capacity of their nanocapsulated derivatives had reached up to 180 J/g. Melting temperature of the solvent n-tetradecanol decreased slightly in the thermochromic systems and further in nanoencapsulated form due to the cryoscopic effect of the non-volatile solutes in the system.
This study deals with preparation, characterization, thermal properties and thermal reliability o... more This study deals with preparation, characterization, thermal properties and thermal reliability of n-eicosane microcapsules as novel phase change material (PCM) for thermal energy storage. The microcapsulated PCMs were prepared by coating n-eicosane with ...
A series of solid-liquid phase change materials, thiourea derivatives, were prepared via condensa... more A series of solid-liquid phase change materials, thiourea derivatives, were prepared via condensation of thiourea with the respective carboxyl chlorides (lauroyl chloride, myristoyl chloride, and palmitoyl chloride) and were then characterized by using FT-IR, 1 H-NMR, differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis. The thiourea derivatives (1,3-didodecanoyl thiourea, 1,3-ditetradecanoyl thiourea, and 1,3-dihexadecanoyl thiourea) were structurally symmetric and had long alkyl groups to crystallize. Thermal analysis by DSC and spectroscopic investigation by FT-IR spectroscopy were performed on the samples before and after thermal cycling tests to determine thermal reliability. The maximum latent heats of melting and freezing of the thiourea derivatives were found to be 114.6 and-110.0 J/g for 1,3didodecanoyl thiourea, 119.5 and-122.4 J/g for 1,3-ditetradecanoyl thiourea, and 148.8 and-142.7 J/g for 1,3-dihexadecanoyl thiourea after accelerated thermal cycling. A TG instrument was used to determine the starting point of degradation in the thiourea derivatives; it was found that the thiourea derivatives degraded at sufficiently higher temperatures than the expected utility temperatures.
Solar Energy Materials and Solar Cells, Mar 1, 2017
Poly(styrene-co-maleic anhydride)(SMA)-graft-polyethylene glycol)(PEG) copolymers were synthesize... more Poly(styrene-co-maleic anhydride)(SMA)-graft-polyethylene glycol)(PEG) copolymers were synthesized as novel polymeric solid-solid phase change materials (S-SPCMs). The synthesized copolymers showed latent heat storage and release ability by means of the phase transition from crystalline phase to amorphous phase of PEG bonded to the skeleton as side chains. The chemical structures of the polymeric S-SPCMs were confirmed by fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1 H NMR) analysis techniques. The transformation of crystalline phase to amorphous phase were investigated using and polarized optical microscopy (POM) techniques. The latent heat thermal energy storage (LHTES) of the S-SPCMs were measured by differential scanning calorimetry (DSC) analysis method. Thermal degradation temperature limits of the S-SPCMs were determined by thermogravimetry analysis (TGA) method. The DSC analysis indicated that the synthesized S-SPCMs demonstrated typical solid-solid phase transitions in the temperature range of about 40-45°C and had considerable high latent heat capacity between 107 and 155 J g −1. The TGA results showed that the polymeric S-SPCMs were durable thermally up to at least 300°C. The thermal cycling test exposed that the S-SPCMs protected their LHTES properties even after 5000 heating/cooling treatment. All findings indicated that the prepared SMA-graft-PEG copolymers posses good thermal energy storage (TES) potential for passive solar heating and cooling applications.
Fatty acids such as stearic acid (SA), palmitic acid (PA), myristic acid (MA) and lauric acid (LA... more Fatty acids such as stearic acid (SA), palmitic acid (PA), myristic acid (MA) and lauric acid (LA) are promising phase change materials (PCMs) for latent heat thermal energy storage (LHTES) applications, but high cost is the major drawback of them, limiting their utility ...
A series of polystyrene-graft-PEG6000 copolymers were synthesized as new kinds of polymeric solid... more A series of polystyrene-graft-PEG6000 copolymers were synthesized as new kinds of polymeric solid???solid phase change materials (SSPCMs). The synthesized SSPCMs storage latent heat as the soft segments PEG6000 of the copolymers transform from crystalline ...
A series of solid-liquid phase change materials, thiourea derivatives, were prepared via condensa... more A series of solid-liquid phase change materials, thiourea derivatives, were prepared via condensation of thiourea with the respective carboxyl chlorides (lauroyl chloride, myristoyl chloride, and palmitoyl chloride) and were then characterized by using FT-IR, 1 H-NMR, differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis. The thiourea derivatives (1,3-didodecanoyl thiourea, 1,3-ditetradecanoyl thiourea, and 1,3-dihexadecanoyl thiourea) were structurally symmetric and had long alkyl groups to crystallize. Thermal analysis by DSC and spectroscopic investigation by FT-IR spectroscopy were performed on the samples before and after thermal cycling tests to determine thermal reliability. The maximum latent heats of melting and freezing of the thiourea derivatives were found to be 114.6 and-110.0 J/g for 1,3didodecanoyl thiourea, 119.5 and-122.4 J/g for 1,3-ditetradecanoyl thiourea, and 148.8 and-142.7 J/g for 1,3-dihexadecanoyl thiourea after accelerated thermal cycling. A TG instrument was used to determine the starting point of degradation in the thiourea derivatives; it was found that the thiourea derivatives degraded at sufficiently higher temperatures than the expected utility temperatures.
Dicarboxylic acid esters for thermal energy storage (TES) have attracted increasing attention in ... more Dicarboxylic acid esters for thermal energy storage (TES) have attracted increasing attention in recent years because of their easy production, offering different temperatures, and providing solutions to the handicaps of fatty alcohols, which are potential TES materials. Dicarboxylic acid esters of 1‐hexadecanol are synthesized herein from adipic, succinic, and oxalic acid for the first time as TES materials. The dicarboxylic acid esters are characterized by Fourier transform infrared and proton nuclear magnetic resonance spectroscopy. Furthermore, the thermophysical properties of the dicarboxylic acid esters are examined by differential scanning calorimetry and thermogravimetric analysis methods. Additionally, the surface morphology features of the dicarboxylic acid esters are determined by polarized optical microscopy. The synthesized dicarboxylic acid esters of 1‐hexadecanol exhibit curiously specific behaviors that they melt at 49.2, 54.1, 54.8, and 53.5 °C, respectively, and crystallize at 47.7, 50.4, 53.1, and 50.2 °C, respectively. The applicability analyses of the dicarboxylic acid esters are carried out with integral graphs showing the sum of sensible and latent heat in a certain temperature range, time‐dependent heating and cooling graphs in a constant increasing temperature environment, and structural and thermal stability analyses after 1000 times heating–cooling thermal cycle.
A D-Mannitol/expanded graphite(EG) composite phase change material(PCM) was prepared for solar th... more A D-Mannitol/expanded graphite(EG) composite phase change material(PCM) was prepared for solar thermal energy storage or waste heat recovery applications performed at 180-240°C. EG was produced by microwave irradiation performed. It was found that the EG prepared exhibited the maximum sorption capacity of 85 wt% for D-Mannitol. Scanning electron microscopy (SEM) images showed that D-Mannitol was uniformly dispersed in the micro holes of EG. Differential scanning calorimeter (DSC) analysis indicated that the phase change temperature of the composite PCM was close to that of D-Mannitol, and its latent heat was equivalent to the calculated value based on the mass fraction of D-Mannitol in the composite. With the assistance of hot disk analyzer, the thermal conductivities of the composite PCM first rise and then drop with increasing of its densities, and similar linear relationships between the maximum thermal conductivity and mass fraction of expanded graphite or between corresponding compress density and mass fraction of expanded graphite were obtained. Thermal energy storage performance of the composite PCM was tested in latent thermal energy storage (LTES) system. The heat transfer in the composite PCM during the thermal energy storage process was enhanced through the thermal conductivity improvement, while the heat storage duration was affected by the mass fraction of EG and the apparent density of the composite PCM.
Solar Energy Materials and Solar Cells, Apr 1, 2011
Erythritol tetrapalmitate (ETP) and erythritol tetrastearate (ETS) were synthesized as novel soli... more Erythritol tetrapalmitate (ETP) and erythritol tetrastearate (ETS) were synthesized as novel solid-liquid phase change materials (PCM) by means of the direct esterification reaction of the erythritol with palmitic and stearic acids. The ETP and ETS esters were characterized chemically using FT-IR and 1 H NMR techniques. The energy storage properties of the esters were determined by DSC analysis. The results indicated that the ETP and ETS esters synthesized as novel solidliquid PCMs are promising materials for thermal energy storage applications at large scale such as solar energy storage, building heating or cooling, indoor temperature controlling, and production of smart textile and insulation clothing.
Journal of Environmental Polymer Degradation, Oct 7, 2009
Link to publication on Research at Birmingham portal General rights Unless a licence is specified... more Link to publication on Research at Birmingham portal General rights Unless a licence is specified above, all rights (including copyright and moral rights) in this document are retained by the authors and/or the copyright holders. The express permission of the copyright holder must be obtained for any use of this material other than for purposes permitted by law. • Users may freely distribute the URL that is used to identify this publication. • Users may download and/or print one copy of the publication from the University of Birmingham research portal for the purpose of private study or non-commercial research. • User may use extracts from the document in line with the concept of 'fair dealing' under the Copyright, Designs and Patents Act 1988 (?) • Users may not further distribute the material nor use it for the purposes of commercial gain. Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
This paper mainly includes the preparation of a novel form-stable composite phase change material... more This paper mainly includes the preparation of a novel form-stable composite phase change material (PCM) by incorporation of lauric acid (LA) within the expanded perlite (EP), characterization of the composite by SEM and FT-IR techniques and determination of thermal properties and thermal reliability of the composite PCM using DSC analysis. The LA could be retained by 60wt.% into EP without
ABSTRACT The interest to innovative products with high added values and processes in textile fiel... more ABSTRACT The interest to innovative products with high added values and processes in textile field has been rapidly increasing among the other industrial fields. One of innovations in this field is to produce of innovative textiles containing phase change material (PCMs) that have thermal storage and thermo-regulation properties. This study deals with preparation and characterization of poly(methylmethacrylate-co-glycidyl methacrylate)/n-hexadecane nanocapsules containing nhexadecane as phase change material for thermal energy storage. The chemical characterization of poly(methylmethacrylateco-glycidyl methacrylate)/n-hexadecane nanocapsules was made by fourier transform infrared (FT-IR) spectroscopy method as particle size and its distribution (PSD) were studied by scanning electron microscopy (SEM). Thermal properties of nanoencapsulated n-hexadecane were determined using differential scanning calorimetry (DSC). The melting and freezing temperatures of the nanoencapsulated n-hexadecane were 17.23 and 14.85 °C respectively as the latent heats of melting and crystallization were 148.05 and −147.63 J/g respectively. Produced nanocapsules were applied to polyacrylonitrile (PAN) by means of electrospinning and surface morphology of the fibers was investigated by SEM analysis. Based on the results, it can be considered that the nanoencapsulated n-hexadecane in poly(methylmethacrylate-co-glycidyl methacrylate) have good energy storage potential to be used in fibers. KeywordsPCM–Smart textiles–Thermal comfort–Thermal energy storage
International Journal of Energy Research, Apr 1, 2020
Polymeric solid‐solid phase change materials (S‐SPCMs) are functional materials with phase transi... more Polymeric solid‐solid phase change materials (S‐SPCMs) are functional materials with phase transition‐heat storing/releasing ability. With this respect, a series of polyethylene glycol (PEG) grafted styrenic copolymer were produced as novel S‐SPCMs. PEGs with three different molecular weights were used for synthesis of isocyanate‐terminated polymers (ITPs). To achieve cross‐linking S‐SPCMs, the ITPs were grafted with styrene‐co‐ally alcohol) (PSAA) at three different PSAA:PEG mole ratios. The produced polymers were characterized using Fourier transform infrared (FT‐IR), proton nuclear magnetic resonance (1H NMR), and X‐ray diffraction (XRD) technique. The crystalline‐amorphous phase transitions of the polymers were examined using polarized optical microscopy (POM). The FT‐IR, NMR, and XRD results confirmed the expected chemical structures and crystallization performances of the polymers. Thermal energy storage (TES) properties of the S‐SPCMs were determined by differential scanning calorimetry (DSC). The DSC results revealed that the polymers with grafting ratio of PSAA:PEG(1:1) had phase transition enthalpies between about 74 and 142 J/g and phase transition temperatures between about 26°C and 57°C. Thermogravimetric analysis (TGA) measurements demonstrated that the S‐SPCMs were resistant to thermal decomposition until about 300°C. Thermal conductivities of the produced S‐SPCMs were measured in a range of about 0.18 to 0.19 W/mK. Furthermore, TES properties of the S‐SPCMs were slightly changed as their chemical structures were remained after 5000 thermal cycles. By overall evaluation of the findings, it can be foreseen that particularly PSAA‐g‐PEG(1:1) polymers can be considered as promising S‐SPCMs for some TES practices such as air conditioning of buildings, thermoregulation of food packages, automobile components, electronic devices, and solar photovoltaic panels.
In this study, the synthesis of new polymer-protein conjugates using a grafting-from strategy was... more In this study, the synthesis of new polymer-protein conjugates using a grafting-from strategy was performed by employing photo-induced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. D-aminoacylase is an industrially significant enzyme for the preparation of chiral amino acids and it is coupled with reversible addition-fragmentation (RAFT) chain transfer agent (CTA) using-activated ester chemistry. The effects of polymeric side chain compositions on the activity of D-aminoacylase were studied with two different polymeric side chain lengths. For this reason, two monomers, a hydrophilic N-(2-aminoethyl acrylamide) and a hydrophobic and N-(iso-butoxymethyl) acrylamide were used, respectively. It was found that modification by grafting from strategy increased the thermal stability of the D-aminoacylase enzyme. Additionally, the hydrophobic monomer conjugate has been reported to increase the activity of the enzyme more than the hydrophilic monomer.
Abstract Three component thermochromic dyes including fluoran type leuco dye, n-tetradecanol, and... more Abstract Three component thermochromic dyes including fluoran type leuco dye, n-tetradecanol, and phenolphthaleinwere prepared and encapsulated in polymethylmethacrylate in this study. Nanoencapsulated system was prepared via oil in water emulsion polymerization technique. According to the morphological investigation by SEM, nanocapsules having spherical shape, compact morphology and lower average diameter around 200 nm were prepared successfully. UV–Visible Spectroscopy analysis and the photographs taken by a digital camera indicated that thermochromic systems and their nanocapsules exhibited reversible color change with thermal stimuli. They were green color at room temperature and lost their color at temperatures upon melting point of the thermochromic systems. In the study, 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone were added to the thermochromic systems to investigate UV resistance of the colorants in the systems. The effect of the UV absorbers on UV resistance of the thermochromic systems was investigated by color measurements based on CIELab system after UV aging of the nanoencapsulated systems. The results proved that especially 2,4-dihydroxybenzophenone was an effective material for increasing UV resistance of the systems and had color developer property. Besides, both thermochromic systems and their nanoencapsulated derivatives exhibited thermal energy storage/releasing property. While thermochromic systems had a heat storage capacity of over 200 J/g, the heat storage capacity of their nanocapsulated derivatives had reached up to 180 J/g. Melting temperature of the solvent n-tetradecanol decreased slightly in the thermochromic systems and further in nanoencapsulated form due to the cryoscopic effect of the non-volatile solutes in the system.
This study deals with preparation, characterization, thermal properties and thermal reliability o... more This study deals with preparation, characterization, thermal properties and thermal reliability of n-eicosane microcapsules as novel phase change material (PCM) for thermal energy storage. The microcapsulated PCMs were prepared by coating n-eicosane with ...
A series of solid-liquid phase change materials, thiourea derivatives, were prepared via condensa... more A series of solid-liquid phase change materials, thiourea derivatives, were prepared via condensation of thiourea with the respective carboxyl chlorides (lauroyl chloride, myristoyl chloride, and palmitoyl chloride) and were then characterized by using FT-IR, 1 H-NMR, differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis. The thiourea derivatives (1,3-didodecanoyl thiourea, 1,3-ditetradecanoyl thiourea, and 1,3-dihexadecanoyl thiourea) were structurally symmetric and had long alkyl groups to crystallize. Thermal analysis by DSC and spectroscopic investigation by FT-IR spectroscopy were performed on the samples before and after thermal cycling tests to determine thermal reliability. The maximum latent heats of melting and freezing of the thiourea derivatives were found to be 114.6 and-110.0 J/g for 1,3didodecanoyl thiourea, 119.5 and-122.4 J/g for 1,3-ditetradecanoyl thiourea, and 148.8 and-142.7 J/g for 1,3-dihexadecanoyl thiourea after accelerated thermal cycling. A TG instrument was used to determine the starting point of degradation in the thiourea derivatives; it was found that the thiourea derivatives degraded at sufficiently higher temperatures than the expected utility temperatures.
Solar Energy Materials and Solar Cells, Mar 1, 2017
Poly(styrene-co-maleic anhydride)(SMA)-graft-polyethylene glycol)(PEG) copolymers were synthesize... more Poly(styrene-co-maleic anhydride)(SMA)-graft-polyethylene glycol)(PEG) copolymers were synthesized as novel polymeric solid-solid phase change materials (S-SPCMs). The synthesized copolymers showed latent heat storage and release ability by means of the phase transition from crystalline phase to amorphous phase of PEG bonded to the skeleton as side chains. The chemical structures of the polymeric S-SPCMs were confirmed by fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1 H NMR) analysis techniques. The transformation of crystalline phase to amorphous phase were investigated using and polarized optical microscopy (POM) techniques. The latent heat thermal energy storage (LHTES) of the S-SPCMs were measured by differential scanning calorimetry (DSC) analysis method. Thermal degradation temperature limits of the S-SPCMs were determined by thermogravimetry analysis (TGA) method. The DSC analysis indicated that the synthesized S-SPCMs demonstrated typical solid-solid phase transitions in the temperature range of about 40-45°C and had considerable high latent heat capacity between 107 and 155 J g −1. The TGA results showed that the polymeric S-SPCMs were durable thermally up to at least 300°C. The thermal cycling test exposed that the S-SPCMs protected their LHTES properties even after 5000 heating/cooling treatment. All findings indicated that the prepared SMA-graft-PEG copolymers posses good thermal energy storage (TES) potential for passive solar heating and cooling applications.
Fatty acids such as stearic acid (SA), palmitic acid (PA), myristic acid (MA) and lauric acid (LA... more Fatty acids such as stearic acid (SA), palmitic acid (PA), myristic acid (MA) and lauric acid (LA) are promising phase change materials (PCMs) for latent heat thermal energy storage (LHTES) applications, but high cost is the major drawback of them, limiting their utility ...
A series of polystyrene-graft-PEG6000 copolymers were synthesized as new kinds of polymeric solid... more A series of polystyrene-graft-PEG6000 copolymers were synthesized as new kinds of polymeric solid???solid phase change materials (SSPCMs). The synthesized SSPCMs storage latent heat as the soft segments PEG6000 of the copolymers transform from crystalline ...
A series of solid-liquid phase change materials, thiourea derivatives, were prepared via condensa... more A series of solid-liquid phase change materials, thiourea derivatives, were prepared via condensation of thiourea with the respective carboxyl chlorides (lauroyl chloride, myristoyl chloride, and palmitoyl chloride) and were then characterized by using FT-IR, 1 H-NMR, differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis. The thiourea derivatives (1,3-didodecanoyl thiourea, 1,3-ditetradecanoyl thiourea, and 1,3-dihexadecanoyl thiourea) were structurally symmetric and had long alkyl groups to crystallize. Thermal analysis by DSC and spectroscopic investigation by FT-IR spectroscopy were performed on the samples before and after thermal cycling tests to determine thermal reliability. The maximum latent heats of melting and freezing of the thiourea derivatives were found to be 114.6 and-110.0 J/g for 1,3didodecanoyl thiourea, 119.5 and-122.4 J/g for 1,3-ditetradecanoyl thiourea, and 148.8 and-142.7 J/g for 1,3-dihexadecanoyl thiourea after accelerated thermal cycling. A TG instrument was used to determine the starting point of degradation in the thiourea derivatives; it was found that the thiourea derivatives degraded at sufficiently higher temperatures than the expected utility temperatures.
Dicarboxylic acid esters for thermal energy storage (TES) have attracted increasing attention in ... more Dicarboxylic acid esters for thermal energy storage (TES) have attracted increasing attention in recent years because of their easy production, offering different temperatures, and providing solutions to the handicaps of fatty alcohols, which are potential TES materials. Dicarboxylic acid esters of 1‐hexadecanol are synthesized herein from adipic, succinic, and oxalic acid for the first time as TES materials. The dicarboxylic acid esters are characterized by Fourier transform infrared and proton nuclear magnetic resonance spectroscopy. Furthermore, the thermophysical properties of the dicarboxylic acid esters are examined by differential scanning calorimetry and thermogravimetric analysis methods. Additionally, the surface morphology features of the dicarboxylic acid esters are determined by polarized optical microscopy. The synthesized dicarboxylic acid esters of 1‐hexadecanol exhibit curiously specific behaviors that they melt at 49.2, 54.1, 54.8, and 53.5 °C, respectively, and crystallize at 47.7, 50.4, 53.1, and 50.2 °C, respectively. The applicability analyses of the dicarboxylic acid esters are carried out with integral graphs showing the sum of sensible and latent heat in a certain temperature range, time‐dependent heating and cooling graphs in a constant increasing temperature environment, and structural and thermal stability analyses after 1000 times heating–cooling thermal cycle.
A D-Mannitol/expanded graphite(EG) composite phase change material(PCM) was prepared for solar th... more A D-Mannitol/expanded graphite(EG) composite phase change material(PCM) was prepared for solar thermal energy storage or waste heat recovery applications performed at 180-240°C. EG was produced by microwave irradiation performed. It was found that the EG prepared exhibited the maximum sorption capacity of 85 wt% for D-Mannitol. Scanning electron microscopy (SEM) images showed that D-Mannitol was uniformly dispersed in the micro holes of EG. Differential scanning calorimeter (DSC) analysis indicated that the phase change temperature of the composite PCM was close to that of D-Mannitol, and its latent heat was equivalent to the calculated value based on the mass fraction of D-Mannitol in the composite. With the assistance of hot disk analyzer, the thermal conductivities of the composite PCM first rise and then drop with increasing of its densities, and similar linear relationships between the maximum thermal conductivity and mass fraction of expanded graphite or between corresponding compress density and mass fraction of expanded graphite were obtained. Thermal energy storage performance of the composite PCM was tested in latent thermal energy storage (LTES) system. The heat transfer in the composite PCM during the thermal energy storage process was enhanced through the thermal conductivity improvement, while the heat storage duration was affected by the mass fraction of EG and the apparent density of the composite PCM.
Solar Energy Materials and Solar Cells, Apr 1, 2011
Erythritol tetrapalmitate (ETP) and erythritol tetrastearate (ETS) were synthesized as novel soli... more Erythritol tetrapalmitate (ETP) and erythritol tetrastearate (ETS) were synthesized as novel solid-liquid phase change materials (PCM) by means of the direct esterification reaction of the erythritol with palmitic and stearic acids. The ETP and ETS esters were characterized chemically using FT-IR and 1 H NMR techniques. The energy storage properties of the esters were determined by DSC analysis. The results indicated that the ETP and ETS esters synthesized as novel solidliquid PCMs are promising materials for thermal energy storage applications at large scale such as solar energy storage, building heating or cooling, indoor temperature controlling, and production of smart textile and insulation clothing.
Journal of Environmental Polymer Degradation, Oct 7, 2009
Link to publication on Research at Birmingham portal General rights Unless a licence is specified... more Link to publication on Research at Birmingham portal General rights Unless a licence is specified above, all rights (including copyright and moral rights) in this document are retained by the authors and/or the copyright holders. The express permission of the copyright holder must be obtained for any use of this material other than for purposes permitted by law. • Users may freely distribute the URL that is used to identify this publication. • Users may download and/or print one copy of the publication from the University of Birmingham research portal for the purpose of private study or non-commercial research. • User may use extracts from the document in line with the concept of 'fair dealing' under the Copyright, Designs and Patents Act 1988 (?) • Users may not further distribute the material nor use it for the purposes of commercial gain. Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
This paper mainly includes the preparation of a novel form-stable composite phase change material... more This paper mainly includes the preparation of a novel form-stable composite phase change material (PCM) by incorporation of lauric acid (LA) within the expanded perlite (EP), characterization of the composite by SEM and FT-IR techniques and determination of thermal properties and thermal reliability of the composite PCM using DSC analysis. The LA could be retained by 60wt.% into EP without
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