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The pristine attapulgite (Atta) was pretreated by thermal and acid activation process in order to improve the loading capacity of phase change material (PCM). A series of pretreated Atta-based composite PCM was prepared combined with different kind of fatty acids. The XRD, FT-IR and XRF results shown that the pretreated process increased the purity of Atta as well as the SEM micrographs and BET results indicated that the porosity of Atta slightly increased after pretreating. What's more, XRD and FT-IR results of the composites PCMs shown good chemical compatibility. DSC results indicated that the composite PCMs of AH-Atta/Lauric acid (LA), AH-Atta/Palmitic acid (SA) and AH-Atta/Docosanoic acid (DA) melted at 42.8 °C, 1.4 °C and 75.2 °C with the latent heat of 94.6 J g−1, 107.5 J g−1 and 84.6 J g−1 at the maximum loading of 51.0%, 50.8% and 51.3%, respectively. In addition, TGA results and 200 thermal cycles test results proved the good thermal stability and reliability of the samples. Based all above results, the prepared composite PCMs have good potential application in energy conservation buildings at different function temperature. [ABSTRACT FROM AUTHOR]

In this study, we focus on important global issue containing both environmental pollution control and energy saving. High density polyethylene (HDPE) is utilized as supporting material to load paraffin, while Al2O3 nano-powder is added into composite behaving as thermal conductivity enhancement to form composite phase change materials (paraffin-Al2O3/HDPE composite PCMs). By the adsorption test and differential scanning calomeritry (DSC) curves, the loading ratio of paraffin in paraffin/HDPE composite is 60%, via taking phase change enthalpy and thermal conductivity into integrated consideration, the adding ratio of Al2O3 is 3% in paraffin-Al2O3/HDPE composite. And CMT4304 universal tester results manifest paraffin-Al2O3/HDPE composites have high compressive strength. For paraffin-Al2O3/HDPE composite with 3 mass% Al2O3, Fourier transformation infrared (FT-IR) result indicates no chemical interaction among raw materials but physical combination. DSC results identify composite PCM happens solid–solid phase transition at 33.3 ºC with enthalpy value of 10.7 J g−1 and melts at 48.8 ºC with enthalpy value of 95.1 J g−1, and thermal cycling measurements demonstrate the form-stable composite PCM with adequate stability after 300 times melting/freezing cycles. Furthermore, the thermal conductivity of paraffin/HDPE composite is enhanced by 119.4% to attain 0.419 Wm−1 K−1 after addition of Al2O3. To sum up, form-stable and tough paraffin-Al2O3/HDPE composite PCMs look promising for application in building field as solar energy utilization materials. [ABSTRACT FROM AUTHOR]

A shape‐stabilized composite phase change material (SS‐CPCM) with paraffin (PA) and biological porous carbon (BPC) was prepared. Freeze‐dried biological‐cellulose include abandoned pomelo peel (APP) and tangerine peel (ATP) were carbonized in vacuum at 800 °C to obtain BPC to be used as a matrix material to prevent PA leakage and enhance thermal conductivity. A vacuum impregnation process was utilized to obtain the SS‐CPCM. Scanning electron microscopy showed that BPC (carbonized APP is subsequently referred to as BPC1 and carbonized ATP as BPC2) has a porous, honeycomb‐like structure, and that the paraffin encapsulated by the pores is evenly distributed. The SS‐CPCM2 (made from ATP) had the highest thermal conductivity (2.10 W/m K), which is 1.89 and 10 times that of the SS‐CPCM1 (made using APP) and pure PA, respectively. Differential scanning calorimetry and thermo‐gravimetric analysis were applied to determine the thermal performance and thermal reliability of the SS‐CPCM. Therefore, the prepared SS‐CPCM has potential in the field of energy storage. [ABSTRACT FROM AUTHOR]

Phase‐change materials (PCMs) have been widely investigated as candidates for thermal energy storage and solar thermal energy conversion. However, low thermal conductivity and poor shape stability during phase transition processes are detrimental to their practical applications. In this study, we designed composite PCMs based on carbon foam (CF) via the vacuum impregnation method to overcome these problems. CF with 3D interconnected microporous structures and good compressive strength was fabricated from phenolic resin (PF) using a combined process of carbonization and sacrificial template techniques. The developer material is considered a promising support material for PCMs. The as‐prepared polyethylene glycol/CF composite (PCC) exhibited a high energy‐storage density with a melting enthalpy of 135.7 J/g, and the thermal conductivity was enhanced by 109.8% compared to that of pure polyethylene glycol. In addition, the PCC showed excellent thermal stability and leakage‐proof performance after 100 heating/cooling cycles and good compressive strength. Because of the simple preparation process and low cost, PCC is a promising material for various thermal energy storage applications, especially in building energy storage systems. [ABSTRACT FROM AUTHOR]

In this study, tetradecanol–palmitic acid/expanded perlite composites containing carbon fiber (TD-PA/EP-CF CPCMs) were prepared by a vacuum impregnation method. Binary eutectic mixtures of PA and TD were utilized as thermal energy storage material in the composites, where EP behaved as supporting material. X-ray diffraction demonstrated that crystal structures of PA, TD, EP, and CF remained unchanged, confirming no chemical interactions among raw materials besides physical combinations. The microstructures indicated that TD-PA was sufficiently absorbed into EP porous structure, forming no leakage even in molten state. Differential scanning calorimetry estimated the melting temperature of TD-PA/EP-CF CPCM to 33.6 °C, with high phase change latent heat (PCLH) of 138.3 kJ kg−1. Also, the freezing temperature was estimated at 29.7 °C, with PCLH of 137.5 kJ kg−1. The thermal cycling measurements showed that PCM composite had adequate stability even after 200 melting/freezing cycles. Moreover, the thermal conductivity enhanced from 0.48 to 1.081 W m−1 K−1 in the presence of CF. Overall, the proposed CPCMs look promising materials for future applications due to their appropriate phase change temperature, elevated PCLH, and better thermal stability. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) require an excellent matrix support material such as porous carbon materials. Orange peel, a discarded, readily available raw material, could potentially be used to prepare biological porous carbon material (BPCM) with abundant pores of uniform size and strong loading capacity through a vacuum freeing method and a carbonization process under nitrogen atmosphere. Herein, paraffin (PA) was encapsulated into BPCM by vacuum impregnation method to obtain environmentally friendly; recyclable PA/carbonized-abandoned orange peel (CAOP) shape-stable PCMs (PA/CAOP SS-PCMs). CAOP was composed of amorphous carbon and a certain degree of graphitization occurred, the best of which was observed following carbonization at 1000 °C. Further, at this temperature, the pores were abundant and PA loading was sufficient. PA/CAOP SS-PCMs were shown to undergo simple physical loading with no chemical interactions and to have good thermal stability and a maximum loading percentage of 88.46%; the calculated maximum loading percentage was of 88.07%. The temperature and latent heat during the melting of PA/CAOP SS-PCMs were 47.68 °C and 180.25 J/g, respectively, and the solidification process occurred 34.47 °C and 177.55 J/g, respectively. The composite exhibited excellent thermal stability and reliability after 200 thermal cycles. Therefore, it has very broad application prospects and value in the fields of energy saving and emission reduction, including solar energy, air conditioning storage cooling systems, and building cladding. [ABSTRACT FROM AUTHOR]

Bone char (BC) is a promising porous material that can be used for preparing a form-stable composite phase change material (PCM). In this paper, form-stable polyethylene glycol (PEG 6000)/BC composite PCMs were prepared by impregnation method. The PEG was used as the phase change material, and two different particle sizes of BC (0.8-1 mm: BC-1; 0.25-0.8 mm: BC-2) were acted as the supporting materials. The phase composition and chemical structure of the composite PCMs (PEG/BC-1 and PEG/BC-2) were characterized using X-ray diffraction and Fourier transformation infrared. The results indicated that the PEG can be well impregnated into BC pores with good compatibility. Thermal properties and thermal stability of the composite PCMs were determined by differential scanning calorimeter (DSC) and thermogravimetry analysis (TGA). DSC results showed that the maximum impregnation percentage for PEG into BC-1 and BC-2 was 38.77 and 43.91%, respectively, without melted PCM seepage from the composites. The TGA analysis revealed that the composite PCMs had good thermal stability above their working temperature range. The thermal cycle test of 100 melting-freezing cycles showed that the composite PCMs have good thermal reliability and chemical stability. The form-stable composite PCMs can be used as thermal energy storage material for waste heat storage and solar heating system. [ABSTRACT FROM AUTHOR]

To overcome the poor shape stability, low thermal conductivity, and weak photo response of phase change materials (PCMs), we designed a kind of Gelatin@nanoGraphite aerogel with aligned channel structure of graphite nanosheets and a new type of stable Paraffin/Gelatin@nanoGraphite composite PCMs was fabricated in this work. The graphite nanosheets were used as thermal conduction and photon absorption fillers. The microstructure, thermal conductivity, thermal stability, and solar-thermal conversion of the composite PCMs have been investigated. The results show that the rich porosity of the prepared Gelatin@nanoGraphite aerogel effectively loads a large amount of paraffin wax (>93.2 wt%). Meanwhile, the composite PCMs had anisotropic solar-thermal conversion and thermal conductivity (radial 3.75 and axial 2.59 W/(m·K)), high melting enthalpy (>146.4 J/g), and excellent phase change cycle and shape stability. This material has intensive application prospects in the fields of building energy saving, human body hyperthermia and solar energy collection system. Paraffin/Gelatin@nanoGraphite PCMs with anisotropic thermal conduction capacity and solar-thermal conversion ability were prepared by directional freeze-drying process and vacuum impregnation. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Carbonization corn cobs were a perfect carrier matrix to form shape stabilized PCMs. • Carbonization corn cobs exhibit a highly porous structure comprising rough micropores. • Latent heat, stability, and thermal properties of PCMs were excellent. • The thermal conductivity of LA-SA/CNCC was 87.5% greater than that of LA-SA. Abstract In this study, novel form-stable composite phase change materials (FS-CPCMs) were prepared by the incorporation of a eutectic mixture of lauric-stearic acid (LA-SA) into carbonization corn cob (CNCC). CNCC served as a good supporting material that not only prevented the leakage of LA-SA but also enhanced its thermal conductivity. Scanning electron microscopy results demonstrated that CNCC exhibits a highly porous structure comprising rough micropores. The retention of 77.9 wt% of LA-SA in CNCC without leakage was observed. Differential scanning calorimetry results revealed that LA-SA/CNCC FS-CPCMs melt at 35.1 °C with a latent heat of 148.3 J/g and solidify at 29.7 °C with a latent heat of 144.2 J/g. The thermal conductivity of LA-SA/CNCC FS-CPCMs was approximately 87.5% greater than that of LA-SA. Thermogravimetric analysis and 200-cycle experiments indicated that the LA-SA/CNCC FS-CPCMs exhibit excellent thermal stability and form-stable performance. Therefore, the as-prepared LA-SA/CNCC FS-CPCMs demonstrate promise for building energy-efficiency applications. [ABSTRACT FROM AUTHOR]

Phase change materials can be incorporated with building materials to make kinds of composite material, which can be applied in building systems due to their excellent thermal energy storage properties. In this study, a novel form-stable composite PCM CA-LA/Diatomite was prepared using vacuum impregnation method by combining a eutectic mixture of capric-lauric acid (CA-LA) as phase change material (PCM) and diatomite as supporting material. The composite products were characterized by using XRD, FT-IR and SEM analyzing methods. The thermal properties of the composite were measured by Differential Scanning Calorimetry (DSC). The results showed that the composite material melted at 23.61 °C with a latent heat of 87.33 J/g and solidified at 22.50 °C with the latent heat of 86.93 J/g. TGA investigation revealed that the composite had excellent thermal durability above their working temperature ranges. The thermal cycling test showed the composite has a good thermal reliability after 200 thermal cycles. What's more, the expanded graphite was added into the composite in order to increase the heat transfer performance. The results showed that the thermal conductivity of the composite increased gradually by 39.7%, 61.6%, 77.6% and 114.2% for the EG fractions of 3%, 5%, 7%, and 10%, respectively. As a result, the CA-LA/Diatomite/EG composite material of has a potential to be applied in modern buildings and solar energy systems due to its excellent thermal properties, good chemical and thermal reliability and high thermal conductivity. [ABSTRACT FROM AUTHOR]

Shape-stable and high-thermal conductivity composite phase change materials (c-PCMs) composed of polyethylene glycol (PEG) and biological porous carbon (BPC) are investigated. BPC based on potatoes and white radishes are obtained by the carbonization method. The thermal conductivity of the BPC increases with the rising of the carbonization temperature due to the higher graphitization degree. Especially, BPC calcined at 1300 °C for 2 h resulted in the optimum PEG supporting matrix candidate, showing an attractive honeycomb-like microstructure. Calcination above 1300 °C results in the destruction of the shape. BPC/PEG c-PCMs are synthesized via a vacuum impregnation approach. PEG equally distributed in the matrix material with a mass fraction of 85.36% approximately and it could keep its morphological stability after heating at 80 °C for 40 h. Moreover, the highest thermal conductivity is 4.5 W/m K, which is about 10 times higher than the pristine PEG. Furthermore, no chemical interaction is found between the PEG and BPC. The melting and solidifying temperature, and enthalpy not vary upon a 200 thermal cycles test. This confirms the excellent chemical and structure stability for c-PCMs, which are within the most promising materials in the area of building heat preservation by being clean, energy-saving and recycled materials. [ABSTRACT FROM AUTHOR]

Currently, phase change materials (PCMs) composite fibers are typically prepared by electrospinning. However, electrospinning exhibits safety concerns and a low production rate, which limit its practical applications as a cost-effective fiber fabrication approach. Therefore, a novel, and simple centrifugal spinning technology is employed to extrude fibers from composite solutions using a high-speed rotary and perforated spinneret. The composite fibers based on polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) were prepared by centrifugal spinning. The SEM of PVP/PEG composite fibers indicated that the fibrous morphology is well preserved. The DSC and TGA indicated that PVP/PEG composite fibers exhibit good thermal properties. [ABSTRACT FROM AUTHOR]

In this study, novel form stable composite phase change materials (FS-CPCMs) from palmitic-lauric acid (PA-LA) eutectic mixture and carbonized abandoned rice (CAR) were prepared via vacuum impregnation. The CAR served as a good supporting material to prevent PA-LA from leaking and enhanced the thermal conductivity of PA-LA. SEM results showed that the CAR has a highly porous structure consisting of rough micro-pores and PA-LA did not leak from the CAR during the solid-liquid phase transition. DSC indicated that the latent heat and temperature of PA-LA/CAR FS-CPCMs during melt were 135.4 J/g and 34.3 °C, respectively, whereas, these values were 124.8 J/g and 28.6 °C during freezing, respectively. The thermal conductivity of PA-LA/CAR FS-CPCMs was 1.83 times that of PA-LA. The heat storage/release rate of the PA-LA/CAR FS-CPCMs is significantly more than that of PA-LA for practical applications. The results obtained from FTIR demonstrated that no new chemical bonds were formed between PA-LA and CAR. TGA and 200-cycle experiments showed that the PA-LA/CAR FS-CPCMs exhibit excellent thermal stability and form-stable performance. The PA-LA/CAR FS-CPCMs thus prepared were safe, environmentally friendly, and cost-effective; hence, they can be used as potential building materials for the applications of thermal energy storage. [ABSTRACT FROM AUTHOR]

Stearic acid (SA) and modified expanded vermiculite (EV) shape-stabilized composite phase change materials (ss-CPCMs) with enhanced thermal conductivity were prepared. EV was impregnated with a starch solution, and then a composite of EV and carbon (EVC) was obtained by carbonizing starch in-situ in the EV layers. 63.12 wt % of SA was retained in the SA/EVC ss-CPCMs without leakage. Scanning electron microscopy (SEM) images showed that the EVC with highly porous micro-pores acted as a good support matrix for absorbing molten SA. The thermal conductivity of the SA/EVC ss-CPCMs was 0.52 W/(m K), and this was an increase of 52.9% compared with that of the SA/EV ss-CPCMs. The results from Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), and thermal cycling tests indicated that the prepared SA/EVC ss-CPCMs are a promising material for energy efficient buildings because of their optimum phase-change temperature, a high enthalpy of phase change, ideal thermal conductivity, and good chemical and thermal stability. [ABSTRACT FROM AUTHOR]

In this study, the effect of the introduction of carbon nanotubes (CNTs) as a filler for enhancing the thermal conductivity of paraffin-carbon nanotubes/expanded perlite form-stable composite phase change materials (PA-CNTs/EP FS-CPCMs) was experimentally investigated. Four samples of PA-CNTs/EP FS-CPCMs with different CNT mass fractions were prepared by vacuum impregnation. Scanning electron microscopy was employed to investigate the morphology and microstructure of CNTs, EP, and PA-CNTs/EP FS-CPCMs. Differential scanning calorimetry was employed to examine the thermal properties of PA-CNTs/EP FS-CPCMs, and results indicated that the latent heat and phase-change temperatures of the PA-CNTs/EP FS-CPCMs slightly change with the CNTs mass fractions. The thermal conductivity of PA-CNTs/EP FS-CPCMs5.27 (0.516 W m −1 K −1 ) was 4.82 times that of PA-CNTs/EP FS-CPCMs0. The thermal storage and release properties of PA-CNTs/EP FS-CPCMs were significantly improved as compared with those of PA-CNTs/EP FS-CPCMs0. Results obtained from Fourier transform infrared spectroscopy, thermogravimetric analysis, and thermal cycling tests showed that PA-CNTs/EP FS-CPCMs exhibit good chemical and thermal stabilities. The as-prepared PA-CNTs/EP FS-CPCMs demonstrate considerable potential as thermal energy storage materials. [ABSTRACT FROM AUTHOR]

In this study, polyethylene glycol/expanded perlite composite with carbon layer phase-change materials were prepared. EP was impregnated with a sucrose solution, followed by carbonation in situ by the carbon-bed method, for obtaining EPC composite, thus providing an important method for enhancing the thermal conductivity of composite PCMs. Scanning electron microscopy images showed that the EPC composite with a highly porous structure composed of rough micro-pores could act as a good supporting material for absorbing molten PEG. The results obtained from differential scanning calorimeter analysis indicated that the values for the latent heat and temperature of PEPC composite during melting were 134.93 J/g and 55.19 °C, respectively, while, these values were 129.27 J/g and 46.71 °C during freezing, respectively. The thermal conductivity of PEPC composite was 0.479 W/(mK), which was 2.975 times that of PEP composite. The results obtained from Fourier transform infrared spectroscopy and thermo-gravimetric analysis showed that PEPC composite exhibited good chemical stability and thermal stability, respectively. Furthermore, thermal cycling tests indicated that PEPC composite exhibited good thermal reliability after 200 melting/freezing cycles. In conclusion, PEPC composite with excellent thermal properties, ideal thermal conductivity, good thermal reliability and chemical stability could act as the promising building filler materials for the sustainable development of energy-efficient buildings. [ABSTRACT FROM AUTHOR]

In this study, novel polyethylene glycol @ Si 3 N 4 nanowires as phase-change materials (PCMs) were developed by using ultrasonic cell disruptor. The results obtained herein indicate that these nanowires can be a potential carrier for preparing PCMs. The results show that PEG is composited in a fluffy nano-network structure of Si 3 N 4 nanowires, which could not be easily leaked from this structure for the solid–liquid phase transition. X-ray diffraction and Fourier transform infrared spectroscopy were employed for investigating the structures of PCMs; the results show that a chemical reaction does not occur between PEG and Si 3 N 4 nanowires. Differential scanning calorimetry analysis results indicated that PCMs exhibit appropriate phase-change temperature and excellent high-phase change enthalpy. From the TGA results, PCMs exhibit perfect thermal stability. The PCMs could perfectly maintain their phase transition after 100 melting–freezing cycles. The thermal conductivity of PCMs-1 was 0.362 W/(mK), which was enhanced by 88.54% in comparison with that to pure PEG. The heat storage or release rate of PCMs is significantly more rapid than that of pure PEG for practical applications. [ABSTRACT FROM AUTHOR]

In this study, novel polyethylene glycol (PEG)/White Carbon Black (WCB) form-stable composite phase changes materials (FS-CPCMs) were prepared by super- ultrasound-assisted, which obviously decreases the reaction time. Test results showed that PEG does not easily leak from the fluffy network structure of WCB during solid-liquid phase transition. Results obtained from XRD and FTIR demonstrated that no new chemical bond is formed between PEG4000 and WCB. Results obtained from DSC and TGA analyses showed that FS-CPCMs exhibit excellent thermal stability and good form-stable performance. The phase change enthalpy of FS-CPCMs reached up to 101.1J/g, and the melting and solidifying times of FS-CPCMs were 34.43% and 30.51% less than that of pure PEG, respectively. The thermal conductivity data showed that WCB acted as the support material is very effective for enhancing the thermal conductivity of the FS-CPCMs. The FS-CPCMs thus prepared were safe, environmentally friendly, and cost-effective; hence, they can be used as potential building materials for the applications of thermal energy storage. [ABSTRACT FROM AUTHOR]

• Hybrid aerogel was prepared by hydrothermal reaction with 3D porous structure. • The PEG mass fraction in c-PCMs was 97.6 wt%. • The H M and H S value of c-PCMs remained 93.44% and 92.84% after 1000 times cycles. • CGA could meet the demand for packing PCM and improving the heat transfer rate. Phase change materials (PCMs) have attracted more and more attention in the field of latent heat storage. In order to solve the leakage behavior and improve heat transfer performance of polyethylene glycol (PEG), a method of self-assembled hybrid aerogel filled with carbon nanotubes (CNTs) combined with reduced graphene oxide (rGO) nanosheets is proposed herein. The as-prepared CNTs-graphene hybrid aerogel (CGA) with three-dimensional porous structure can be used as a highly adsorptive and stable carrier for PCM. After the vacuum impregnation process, a high-performance PEG/CGA composite PCMs (c-PCMs) is obtained, which exhibits an outstanding PEG loading ratio of 97.6 %. Moreover, after 1000 repeated heating/cooling cycles, the H M and H S value of PEG/CGA c-PCMs remained 93.44 % and 92.84 %. Meanwhile the PEG/CGA c-PCMs remains intact and the loading ratio could still maintain as high as 96.4 %, which proved that PEG/CGA c-PCMs presented reliable thermal cycling stability. The PEG/CGA c-PCMs only takes 603 s to raise from 30 ℃ to 70 ℃, which is much faster than that of pure PEG (813 s) and PEG/GA composite (727 s). And The thermal conductivity of PEG/CGA(0.586 W/(m∙K)) was 186 % times than that of pure PEG(0.314 W/(m∙K)).The introduction of CNTs can not only enhance the adsorption capacity of c-PCMs and alleviate the leakage of PEG, but also improve the heat transfer performance of c-PCMs. These results specify that PEG/CGA c-PCMs can be used as remarkable and stable energy storage materials for environmental thermal management systems. [ABSTRACT FROM AUTHOR]

Currently, electrospinning technology is the most used spinning technology. However, electrospinning exhibits low production rate and safety hazards, which has led to the development of the novel centrifugal spinning technology to extrude phase change fibres from composite solutions. The flexible composite phase change fibres based on Polyethylene glycol (PEG) and Polyvinylpyrrolidone (PVP) were prepared by centrifugal spinning. Moreover, carbon nanotubes acted as thermally conductive fillers to enhance the thermal conductivity of flexible composite phase change fibres. The microstructures of the fibres were observed with a scanning electron microscope (SEM). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to determine the thermal properties of the fibres. The results showed that the concentrations of PEG and PVP had different influences on the diameter and smoothness of fibres, and the energy storage effect increased with the increasing PEG content. In summary, flexible composite phase change fibres based on PEG and PVP have very good application prospects for thermal insulation. Morphology and microstructure of centrifugal spinning composite fibres: (a) CNTs 1 wt %, (b) CNTs 3 wt %, (c) CNTs 5 wt % and (d) CNTs wrapped in composite fibres. Image 1 • The composite fibres with energy storage effect was prepared by centrifugal spinning. • PEG is encapsulated in PVP fibres with no leakage. • The thermal conductivity of the composite fibres with CNTs is 1.71 times higher than that of without CNTs. • The preparation process of the composite fibres was cost-effective, environment friendly, chemically stability, and harmless. [ABSTRACT FROM AUTHOR]

• The study focuses on a novel matrix material for loading phase change material. • Anodizing surface treatment is applied to preparing nano-porous TS-AS. • Nano-porous TS-AS can improve thermal conductivity and stability of composite PCM. • TS-AS/1-TD composite behaves excellent sustainability to guarantee long-term service. In this study, an innovative matrix material has been designed and prepared for supporting phase change materials (PCMs) to optimize the thermal property of composite PCM. The abandoned thin-slice aluminum substrate (TS-AS) is etched electrochemically into porous layer with peak-valley structure via anodizing surface treatment, nano-porous Al 2 O 3 film growing on the TS-AS surface is used to encapsulate 1-tetrapropanol (1-TD) to prepare nano-porous TS-AS/1-TD composite PCM. According to thermal properties test results, the melting temperature and phase change latent heat (PCHL) of TS-AS/1-TD composite are 36.9 °C and 97.4 J/g, and its thermal conductivity is enhanced by 560.0% compared to pure 1-TD by introducing porous TS-AS, both these thermal properties show excellent sustainability maintaining only ±1.4% variation even after 400 times melting/freezing thermal cycles, while the composite PCM performs good thermal stability beyond 144.7 °C, which enables them to behave as thermal energy absorbing materials applied to cooling the generated heat from running precision device. Besides, the anodizing mechanism inspires the further optimization of aluminum substrate or other metal substrates by regulating porous layer morphology and thickness. [ABSTRACT FROM AUTHOR]

In this paper, a composite phase change material based on paraffin and carbon foam derived from starch was prepared. The paraffin was encapsulated in the carbon foam, which was prepared by using a foaming and steaming method at different carbonization temperatures. Carbon foams comprised amorphous carbon and were impregnated with paraffin to obtain the paraffin/carbon foam composites (PCCs). When carbonized at 1100 °C, the loading percentage of the carbon foam enabled to reach maximum 72.79%. Paraffin encapsulation did not result in any new structure or chemical bonds involved or change in the geometry. The latent heats of the sample were 174.3 J/g at the melting temperature (47.9 °C), and 151.4 J/g at the freezing temperature (52.8 °C). Thermal conductivity of PCCs reached up to 1.93 times than that of paraffin. The composite phase change material fabrication was cost–effective, environment friendly, chemically stable, and suitable for energy–efficient building applications. Image 1 • The carbon foam with hierarchical pores was prepared by traditional thermal fermentation and steaming method. • The paraffin was encapsulated in the carbon foam without any new structure or chemical bonds involved in the geometry. • Thermal conductivity of the composite phase change materials reached up to 1.93 times that of paraffin. • The composite PCM fabrication was environment friendly , and suitable for energy–efficient building applications. [ABSTRACT FROM AUTHOR]

In this study, an innovative carbon fiber reinforced polymer (CFRP) that obtains thermal storage property by implanting expanded graphite (EG)/paraffin (Pa) composite into carbon fiber interlayer (CFRP-EG/Pa composite) has been synthesized. In the CFRP-EG/Pa composite, EG/Pa composite plays a critical role in bringing about function of thermal storage for the whole composite, making CFRP composite with 9 wt% EG/Pa as an example, differential scanning calorimetry (DSC) result manifests it has melting enthalpy of 12.78 J/g and freezing enthalpy of 12.91 J/g. Besides, EG/Pa composite also contributes to improving the strength, the result demonstrates that flexural strength like CFRP-6wt%EG/Pa has been enhanced by 15.4%, and flexural strength achieves improvement at 65 °C even Pa stays in a molten state compared to CFRP without EG/Pa composite. The melting/freezing thermal cycles results reveal that CFRP-EG/Pa composites have stable and sustainable property, flexural strength have just varied in the ±1.8% interval and above two enthalpy values also change beyond 1.9% after 400 times and 800 times thermal cycles. The thermogravimetric (TG) result indicates CFRP-EG/Pa composite can be applied safely beyond 246.59 °C. Therefore, CFRP-EG/Pa composites have sustainable mechanical property and thermal property to broaden their application. [ABSTRACT FROM AUTHOR]

Recently, electrospinning has been widely applied to prepare phase-change material fibres. However, the practical applications of electrospinning are limited by its low productivity and potential safety hazards. Herein, a simple centrifugal spinning without the drawbacks of electrospinning was applied to fabricate polyethylene glycol-based PCM fibres with nano-SiC as a highly conductive filler, polyacrylonitrile as the supporting material, and N,N-dimethylformamide as the solvent to dissolve the polymers. Results demonstrate that the PCM fibres were formed by physical combination rather than chemical reaction. The shapes of the PCM fibres remained stable during the phase-change process. Based on differential scanning calorimetry, PAN/PEG/SiC PCM fibres containing 4.0 wt% nano-SiC melted at 51.31 °C with a phase-change latent heat of 69.91 J/g. The thermal conductivity of PAN/PEG/SiC PCM fibres was improved by 79% compared to that of PAN/PEG PCM fibres. The good thermophysical properties of the prepared PAN/PEG/SiC PCM fibres show promise for long-term utilization. Image 1 • The PAN/PEG/SiC PCM fibres were prepared by centrifugal spinning. • The polyacrylonitrile (PAN) was satisfactory PEG supporting matrix. • The relationship of highly conductive filler (nano-SiC) and thermal conductivity was deep investigated. [ABSTRACT FROM AUTHOR]