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Paraffin- and titania (TiO2)-based nano-encapsulated phase change materials (NePCMs) were synthesized by the sol–gel process to improve thermal as well as phase change performance. Nine different samples of NePCMs were prepared by varying core/shell mass ratios, and their effect was investigated on thermal performance. The paraffin/TiO2 nanocapsules were characterized by Fourier transform infrared spectrophotometer (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and dynamic light scattering (DLS). The characterization techniques confirmed that the paraffin was successfully contained in the TiO2 shell. The maximum effective melting (73.47 Jg−1) and solidification (71.87 Jg−1) latent heat for the NePCMs were found to be at a 52.33% encapsulation ratio. The mean size of the NePCMs was approximately 238 nm measured from DLS. The thermal properties of the same sample stayed almost the same even after 100 thermal cycles validated by the differential scanning calorimetry (DSC) curves, and thermal stability was evaluated by a thermogravimetric analyzer (TGA). [ABSTRACT FROM AUTHOR]

The use of phase change materials (PCMs) for thermal storage, thermal management, and thermal insulation has been widespread for many years. Thermal storage systems (TES) based on PCMs can be improved and optimized by adding nanoparticles (NPs) to them. Throughout this study, PCM nanocomposites (NCs) based on paraffin wax (PW) loaded by anatase titania (TiO2) NPs were fabricated and characterized to examine their thermal performance as phase change materials. The as-synthesized TiO2 NPs were obtained by hydrolysis technique and showed a well-defined spherical shape with a diameter in the nanoscale range and a crystallite size ~ 22.75 nm. Throughout the used concentrations of TiO2 NPs, 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, and 0.5%, the morphological feature for the PW/TiO2 NCs revealed a good dispersion of NPs in PW. The non-isothermal differential scanning calorimetry (DSC) measurements at a constant heating rate of 10 °C min−1 were used in order to get the melting point (Tm), latent heat of fusion (LH), and latent heat rate (LHR) as a function of TiO2 NP concentrations for the investigated PW/TiO2 NCs. Both LH and LHR values for PW/TiO2 NCs are higher than those obtained for a pure PW sample. The significant enhancement in LH and LHR values for PW/TiO2 NCs was found to be 21.2% and 134.3% in comparison with the pure PW sample, respectively. The thermal stability of the investigated PW/TiO2 NCs was examined using thermal gravimetric (TG) scans. It is found that the thermal stability varies with TiO2 NP concentrations with a non-monotonic trend. At concentrations up to 0.25 mass%, the thermal stability improved. For concentrations over 0.25 mass%, the degradation process became rapid. [ABSTRACT FROM AUTHOR]

Devices of solar water desalination confront many problems including the low thermal properties of phase change materials (PCMs) such as heat transfer, storage of heat capacity, charging and discharging capability. Thus, these properties need to be improved by using a simple and novel procedure. So, incorporation and dispersion of hybrid nano-powders inside PCMs is considered a simple and novel procedure to improve the thermal properties of solar water desalination devices. The present article is focused on incorporating different nano-powders of MWCNTs and Al2O3 inside PCMs to improve the thermal characteristics of solar water desalination applications. Different nano-powders of MWCNTs and Al2O3 have been incorporated as: (i) 1.0 mass% Al2O3, (ii) 1.0 mass% MWCNTs, and (iii) hybrid 1.0 mass% of Al2O3 + 1.0 mass% MWCNTs, inside a constant amount of 250 gm RT-65HC paraffin wax. An innovative prototype was designed and produced to measure the thermal characteristics of solar water desalination devices. Various analyses have been carried out to study the influence of nano-powders scattering on the morphological, microstructural observations, chemical and thermal characteristics, including SEM, XRD, FT-IR, TGA, DSC, thermal conductivity, and infrared thermography. Microstructural observations showed that the excellent dispersion of nano-powders was at hybrid nano-additives of 1.0 mass% MWCNTs + 1.0 mass% Al2O3 inside PCMs. The uniform scattering of hybrid 1.0 mass% MWCNTs + 1.0 mass% Al2O3 inside PCMs assists to eliminate any defects. Finally, thermal characteristics of hybrid nano-additives phase change materials (NAPCMs) were improved specially in thermal stability, latent heat temperature, and thermal conductivity at 89%, 80%, and 32.8%, respectively. [ABSTRACT FROM AUTHOR]

The research article addresses the effect of multi-wall carbon nanotube (MWCNT) and nano-boron nitride (NBN) hybrid composite powders on thermal properties of the paraffin wax for thermal storage applications. Five different phase change material (PCM) samples were prepared with 100 paraffin wax, 99.5 paraffin wax + 0.5 MWCNT, 99.5 paraffin wax + 0.5 BN, 99 paraffin wax + 0.5 MWCT + 0.5 BN and 98 paraffin wax + 1 MWCNT + 1 BN mass percentage compositions. The size of the secondary particles MWCNT and NBN was assessed using transmission electron microscope (TEM). After PCM preparation, the morphology and distribution of the secondary particles were evaluated using field emission scanning electron microscope (FE-SEM). The phase change of MWCNT and NBN was evaluated using X-ray diffraction (XRD) technique. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and thermal conductivity tests were carried out on the PCMs to assess physical and thermal properties. The results revealed that hybrid nano-composite powders with paraffin wax provide better thermal conductivity of paraffin wax which increased from 0.18 to 0.31 W m−1 K−1. However, the distribution of MWCNT and NBN extended the thermal degradation of paraffin wax and solidification temperature. Increasing the mass % of MWCNT and NBN reduced the melting point of paraffin wax from 64.70 to 62.52 °C. Further, the solidification temperature of paraffin wax increased while increasing the mass % of MWCNT and NBN from 56.01 to 60.13 °C. This research revealed that thermal properties of paraffin wax were significantly increased with the increment of mass % of composite powders (MWCNT and NBN) addition. [ABSTRACT FROM AUTHOR]

The focus of this research was on the thermal conductivity and rheological properties of poly(ethylene glycol) with a molecular mass of 200 g mol−1 (i.e., PEG200) loaded with four different types of multi-walled carbon nanotubes (MWCNTs) in a wide concentration range up to 10 mass%. MWCNTs used differ in size (both diameter and length) and the content of COOH (oxidized) functional groups on their surface. It was found that the use of oxidized, shorter and wider MWCNTs in PEG200 results in highest enhancement in thermal conductivity by 133% for 10 mass% MWCNTs-PEG200 nanofluids. Investigation of the shear rate dependence of dynamic viscosity (η) showed that the use of MWCNTs in concentrations greater than 0.1 mass% changes the Newtonian behavior of PEG200 and results in the shear-thinning behavior. This behavior is strongly influenced by the MWCNT concentration in the nanofluid. When comparing the same nanofluid concentration, the highest degree of MWCNT agglomeration in PEG200 nanofluids was observed when long, thin and pristine MWCNTs were used. The thermal conductivity results were correlated with the most commonly used theoretical models: Maxwell, Hamilton-Crosser, Xue, and Murshed. Dynamic viscosity results were correlated with Einstein, Brinkman, and Brenner-Condiff theoretical models. The best agreement with the experimental results was obtained by the Maxwell and Einstein models, indicating the formation of sphere-like MWCNT agglomerates in each PEG200 nanofluid studied. [ABSTRACT FROM AUTHOR]

Wood impregnated with a multicomponent mixture of fatty acids as a bio-based phase change material (BPCM) to improve its thermal characteristics was studied. The studied wood/BPCM composites can be used as internal elements in buildings for energy storage. Scots pine and beech sapwood were impregnated with a multicomponent mixture of linoleic acid and coconut oil fatty acids at a ratio of 20:80. Leakage test was conducted and revealed that the maximum leakage for pine and beech were 9 and 8%, respectively. Light microscopy was employed to demonstrate the distribution of the BPCM in the wood structure. Rays in both pine and beech wood served as pathways for impregnation of the BPCM to partly fill the tracheid lumens (pine) and vessels (beech). Thermal characterization of the studied samples employed T-history and DSC methods, concluding that the impregnated wood had significant thermal mass, ability to store excessive energy in terms of latent heat and keep the temperature constant for long time. The specific heat capacity of the impregnated samples was 4–5 J g−1 K−1 i.e., higher than that of the untreated control samples of ca. 2 J g−1 K−1. The thermal conductivity of the samples before and after the impregnation was measured using heat flow meter method and the results showed that the untreated beech wood had higher thermal conductivity compared to pine and the parameter improved when the cell lumens were filled with the BPCM. Scots pine wood with to 80% mass percentage gain (MPG) after impregnation demonstrated an increment in thermal conductivity of 33% while Scots pine and beech with 43 and 38% MPG demonstrated an increase of the conductivity with 8 and 11%, respectively. [ABSTRACT FROM AUTHOR]

Thermoregulating composites were produced by using a thermoregulating slurry (NPCS) containing nanoencapsulated phase change material (NPCM) from poly(styrene-co-divinylbenzene) as shell and the commercial paraffin Rubitherm®RT27 as core material. These composites were synthesized by using the constitutive water of the slurry as setting water and changing the NPCM/Hemihydrate (NPCM/Hem) mass ratio within 0.0–0.41. It was found that nanoparticles were uniformly dispersed into the gypsum, and the gypsum crystal morphology was tuned by the addition of the slurry. Attending to the thermal properties, these materials can work either as insulating or thermal energy storage materials, decreasing the thermal conductivity up to ~ 50%, whereas the thermal energy storage (TES) capacity is enlarged in a ~ 140%, respect to the pure gypsum, when the maximum NPCM/Hem mass ratio was used. This composite had a latent heat of 30.2 J g−1 and a heat capacity of equivalent 3.5 J g−1 K−1. Composites from a NPCM/Hem mass ratio up to 0.15 satisfied European mechanical standard EN 13,279–1 for gypsum binders and gypsum plasters and all of them, presented a bulk density higher than 0.60 g cm−3. The addition of a 41% in mass of nanocapsules allowed to save 13.5 kWh m−3 and, reducing the CO2 emissions up to 3.4 kg of CO2 per operating cycle. The use of this new material would lead to significant energy and economic savings, as well as a considerable reduction in the emission of polluting gases into the atmosphere. [ABSTRACT FROM AUTHOR]

In this study, a series of phase change nanocomposites using microencapsulated phase change material and graphene nanoplatelet (as an additive material) is synthesized to enhance PCM thermal properties. Paraffin as a PCM is encapsulated by melamine–formaldehyde as a shell material via in situ polymerization method. Graphene nanoplatelet as a heat transfer promoter is added among the microencapsulated phase change materials (MPCMs) in different mass fractions to form phase change nanocomposites. By the applied technique, the defect of leakage and the low thermal conductivity of the phase change material can be overcome simultaneously. The experimental measurements show that the thermal conductivity of the PCNs effectively enhances without a significant influence on their phase change enthalpy. The results indicate that when the amount of the graphene nanoplatelets increases, the thermal diffusivity and thermal conductivity enhance. By using 10 mass % graphene nanoplatelets in the PCN, the PCN's thermal diffusivity and thermal conductivity are raised by 93% and 48%, respectively. The DSC results show that the maximum latent heat of the PCNs is 95.97 J g−1 (PCN with 1 mass % of graphene). However, the maximum difference in the latent heat of PCNs with different graphene percentages is less than 4%. Thermal stability experiments show that the PCNs have a stable structure up to 165 °C without damaging the microcapsule shell. The fabricated PCNs, compared to many previous works, have good thermal properties and low cost which can properly be considered in thermal energy storage and thermal management applications. [ABSTRACT FROM AUTHOR]

A novel smart solid-gel phase change materials (PCMs) with the photoluminescence and thermochromic properties were designed and fabricated in a simple way. In this work, luminescent mesoporous alumina (LMAa) was firstly prepared through pomelo peel bio-template method, which showed a better photoluminescence performance under the condition of 254 nm light. Next, LMAa and thermochromic pigment (TP) were evenly dispersed in the gelled capric–myristic–stearic fatty eutectic (CA-MA-SA) using magnetic stirring method, in which hydroxypropyl cellulose served as gelling agent, CA-MA-SA as good thermal storage PCM, LMAa as excellent fluorescent material, and TP as visible temperature change indicator. Some advanced techniques were introduced to characterize physical, chemical, and thermal properties of composite PCMs. Results showed that the CA-MA-SA/LMAa1.0 displays obvious luminescence under 254 nm UV light, excellent thermochromic ability from off-white to red as rising the ambient temperature from 35 to 45 °C, limited fluidity at 60 °C, suitable phase change temperature around 19.11 °C, high latent heat about 114.3 J g−1, and so on. The ideal shape stability, thermal, photoluminescent, and reversible thermochromic properties of composite PCMs had not only great application prospect in the field of thermal energy storage, but also brought convenience in practical application. [ABSTRACT FROM AUTHOR]

Polyethylene glycol (PEG) is widely used as phase change materials (PCMs). However, the leakage and low thermal conductivity issues restrict its practical application. Herein, a series of novel MWCNTs/HPC/PEG PCMs (named as PCMMHP) have been synthesized by hydroxypropyl cellulose grafting onto PEG for the first time and doping multi-walled carbon nanotubes (MWCNTs). The results indicate that the PCMMHP exhibit excellent shape stability and without leakage keeping warm for an hour at 353.2 K. The melting and freezing enthalpy of the PCMM1HP7 is 134.7 J g−1 and 131.2 J g−1, respectively; and corresponding melting point and crystallization temperature are about 324.9 K and 308.8 K, respectively. The PCMMHP show a good reversible thermal stability after 100 heating/cooling cycles. In addition, adding 4 mass% MWCNTs, the PCMM4HP7 possess a higher thermal conductivity of 0.6019 W m−1 K−1, which is 2.1 times that of the PCMHP without MWCNTs (0.2895 W m−1 K−1) and 1.9 times that of pure PEG (0.3228 W m−1 K−1). In a word, the fabricated PCMMHP is a kind of shape-stabilized PCM and has good latent ability. It will have a broad potential application in thermal energy storage applications. [ABSTRACT FROM AUTHOR]

In order to adjust buildings temperature, a dodecanol (DD)-palmitic acid (PA)/hydroxylpropyl methyl cellulose (HPMC) composite phase change material was prepared by vacuum impregnation. DD-PA was absorbed into the HPMC, which was verified by specific surface area, pore size (BET) and scanning electron microscopy (SEM) analysis. The results of Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD) indicated that the HPMC and DD-PA were only physical combination. The differential scanning calorimetry (DSC) analysis revealed that the phase change temperature and latent heat were 19.34 ºC and 113.12 J g−1, which means good energy storage capacity. The 5% mass loss temperatures (T-5%) of thermo-gravimetric analysis (TG) was higher than 50 ºC, showing the good thermal stability of composite phase change materials. About 60% DD-PA was absorbed in HPMC, which detected by DSC and TG. After 100 thermal cycling, the latent heat, onset temperature (T0), peak temperature (Tpeak) and end temperature (Tend) had changed −1.02%, −8.20%, −4.29% and −5.60%. The result showed that the composite phase change materials own good thermal reliability. In addition, the 2% multi-walled carbon nanotubes (MW CNTs) were added to improve the thermal conductivity. And the thermal conductivity was increased from 0.130 to 0.172 W (mK)−1, the total thermal storage-release time was decreased from 3740 to 2310 s. [ABSTRACT FROM AUTHOR]

The different MSEP/SA composite phase change materials were prepared by direct impregnation method with SEP-v, SEP-p, SEP-f as supporting material. The thermal stability of the composite phase change materials was analyzed and the differences in the thermal properties and thermal reliability were compared, and provided reference for the study of different SEP to adsorb stearic acid (SA). The results indicated that there is no chemical reaction during the preparation of the composite PCMs. SEP-f has great advantages as a supporting material and its composite (65SEP-f/SA) has a good leak-proof performance with remaining mass ratio is above 99% for leakage test of 50 h. Besides, melting and freezing latent heat of three composite PCMs are similar, For 65SEP-f/SA, the melting latent heat is 76.10 J g−1 corresponds to the phase change temperature of 344.15 K and the freezing latent heat is 75.59 J g−1 corresponds to the phase change temperature of 336.85 K. The 65SEP-f/SA has the highest thermal conductivity of 0.9460 W m−1 K−1. It can be conducted that 65SEP-f/SA have great application potential in the field for low temperature phase change energy storage. [ABSTRACT FROM AUTHOR]

MnO2 particles were prepared by a hydrothermal method and characterized via the SEM imaging, XRD and FTIR analyses, showing that the individual particles were spherical and less than 1.0 μm in diameter but were clustered in α type crystal. The particles were then added into the n-octadecane to form a new class of phase-change energy storage composites. After that, the composite powder was wrapped into polyethylene by the suspension polymerization, forming microcapsules with an average size 4.9–5.6 μm in diameter. Eventually the morphology and thermal properties of the microcapsules were analyzed. No forming of chemical bond between the core material and the shell material was found during the microcapsule synthesis process. The latent heat and encapsulation efficiency of the microcapsules with addition of 0.5 mass% MnO2 particles in the n-octadecane were measured at 107.5 ± 1.3 J g−1 and 95.3 ± 1.2%, respectively, which are higher than the microcapsules with pure n-octadecane, measured at 84.9 ± 1.2 J g−1 and 75.3 ± 1.4%, respectively. The thermal conductivity of the n-octadecane microcapsules modified with 0.5 mass% MnO2 was enhanced by about 103.3% at 15.0 °C compared with the microcapsules without MnO2. Thermogravimetric and thermal cycling studies showed that the modified new microcapsules had good thermal stability. Such a modification provided an effective way to prepare phase-change energy storage microcapsules with better thermal properties and higher encapsulation efficiency. [ABSTRACT FROM AUTHOR]

In this work, polyurethane (PU) insulating panels containing different amounts of a microencapsulated paraffin with a nominal melting temperature of 24 °C, used as phase change material (PCM), were produced. The resulting panels behaved as multifunctional materials able to thermally insulate and simultaneously storing/releasing thermal energy near room temperature. The panels were characterized from a microstructural, thermal and mechanical point of view. Viscosity measurements highlighted an increase in the viscosity values of the PU liquid precursors due to the addition of the capsules, and this could lead to some difficulties during the production stages, especially in the mixing and foaming phases. From optical microscopy micrographs and density measurements, it was observed that the introduction of paraffin tended to destroy the cellular structure of PU foams, and for PCM contents above 30 mass/% the foams were characterized by an open-cell morphology. SEM observations showed that PCM was preferentially distributed in the cell walls intersection, and a rather limited interfacial adhesion between capsules and PU could be detected. Thermogravimetric analysis evidenced that the introduction of the PCM tended to increase the degradation resistance of the foams, while from differential scanning calorimetry tests it was possible to conclude that PCM addition was able to impart good thermal energy storage properties to the foams, with specific melting enthalpy values of 70 J g−1 for a microcapsules concentration of 50 mass/%. As expected, thermal conductivity (λ) of the foams increased with PCM amount, but this enhancement was not directly related to the higher λ of the PCM itself, but rather than to the cell opening effect promoted by the PCM introduction. The microcapsules addition progressively increased the stiffness of the foams, reducing the failure properties both under quasi-static and impact conditions. Moreover, the mechanical properties were strongly affected by the testing temperature (i.e. the physical state of the wax contained in the microcapsules). [ABSTRACT FROM AUTHOR]

The present work deals with thermal energy storage behavior of the nano-enhanced phase change materials (NEPCMs) for building space cooling application. The NEPCMs have been prepared using Deionized (DI) water as the base phase change material (PCM) and multi-walled carbon nanotubes (MWCNTs) as nanomaterial with mass concentration of 0.25%, 0.5%, and 0.75%. For better stability of additive materials in the base PCM, sodium dodecyl-benzene sulfonate (SDBS) has been chosen as an additive element. The sub-cooling of the DI water has been completely eliminated for a mass concentration of 0.75% of MWCNT. The differential scanning calorimetry(DSC) analysis has been conducted to measure the phase transition properties of NEPCMs. The enhancements of 12.8% and 14.13% in latent heat values for charging and discharging processes, respectively, were observed for maximum mass concentration. It has also been observed that the onset temperature for charging is reduced from − 12.8 to − 9.7 °C for NEPCM with maximum concentration. The maximum thermal conductivity (k) augmentation of 23% (solid phase) and 11.2% (liquid phase) has been achieved by the NEPCM having a mass concentration of 0.75% MWCNT at − 10 °C and 15 °C, respectively. According to the study results the reductions in total charging times are 28% and 19% with the NEPCM holding a mass concentration of 0.75% MWCNT for − 8 °C and − 6 °C heat transfer fluid (HTF) temperatures, respectively. The environmental pollution remediation can be achieved by the reduction in energy input to the chiller by minimizing the total time taken for the charging the PCM. [ABSTRACT FROM AUTHOR]

Energy storage plays an important role in improving the applicability of a wide range of energy systems. Buildings could be considered as a desirable place for this purpose. Incorporating phase change materials (PCMs) as form-stable composites into the building materials has been widely taken into consideration in recent years. However, there are still some shortcomings in applying this technique. In this study, we focused on a surface modification method to prevent leakage of PCM from porous aggregates during heating/cooling cycles. Paraffin (PA) as phase change material was impregnated into the expanded perlite (EP) particles by vacuum impregnation method, and prepared EP/PA composite was coated by a layer of polystyrene. Thermal characterization of obtained composite samples was conducted by DSC and TG analysis. Also, a simple apparatus was prepared to evaluate thermal behavior of a concrete block made by these modified form-stable PCMs during the heating process. Oozing circle method and visual observation for leakage were conducted for surface-modified EP/PA particles and final concrete blocks, respectively. Finally, compressive strength test was applied to evaluate the feasibility of using concretes made by EP/PA composites as structural concrete. The results showed that using polystyrene as a coating material for EP/PA particles was a promising method for PCM leakage prevention. Latent heat value decreased about 18% for surface-modified EP/PA but no leakage trace was observed; also in spite of decreasing in compressive strength up to 40%, it is still in acceptable range for structural purposes. [ABSTRACT FROM AUTHOR]

In this paper, ultrasonic dispersion and surface chemical modification were used to prepare the modified multi-walled carbon nanotubes (MWNTs)/paraffin composite phase-change materials (PCMs). The surface modification of MWNTs was developed via coating MWNTs with silica dioxide. The modified MWNTs were marked as SiO2@MWNTs. The phase-change properties, thermal stability and chemical functional groups of the MWNTs/paraffin composite PCMs were measured by differential scanning calorimetry, thermogravimetric analysis (TG) and Fourier transform infrared spectroscopy, respectively. The results indicated that paraffin and MWNTs were compound physically. The diameter and content of MWNTs had influence on the phase-change temperature and the latent heat of the MWNTs/paraffin composite PCMs. The smaller the diameter or larger content of the SiO2@MWNTs, the greater the influence was. The reduction degree of PCM1(the diameter of the SiO2@MWNTs is 20–30 nm) in latent heat is about 4.5 times of that of PCM3(the diameter of the SiO2@MWNTs is larger than 50 nm). The thermal stability and the thermal conductivity of the composite PCMs were improved with the addition of the SiO2@MWNTs. When the content of SiO2@MWNTs is 5 mass%, the thermal conductivity of the paraffin PCMs is 0.383 W m−1 K−1). [ABSTRACT FROM AUTHOR]

Solar PV panel cooling is essential to achieve maximum efficiency of PV modules. Phase-change material (PCM) is one of the prominent options to cool the panel and reduce the temperature, since PCMs have low thermal conductivity. Expanded graphite particles are used to enrich the structure and stability as well as to increase the thermal properties. In the present research work, polyethylene glycol (PEG) 1000 is used as a base material and expanded graphite for inclusive particle. A novel form-stable PEG1000/EG composite PCM mixture is prepared, using impregnation and dispersion method. Expanded graphite and PEG1000/EG sample phase compositions are investigated, using X-ray diffraction technique. No new peak is identified in the composite PCM sample. The surface morphology and structure of EG and PEG1000/EG are investigated, using scanning electron microscopy (SEM). Chemical stability analysis is done by Fourier-transform infrared spectroscopy. Thermal properties of the prepared composite PCMs are analysed by differential scanning calorimetry, thermogravimetric analysis (TGA) and KD2 pro analyser. Results show that addition of EG in various propositions (5%, 10% and 15%) enhances the thermal conductivity of PCM samples from 0.3654 to 1.7866 W mK−1, while melting point and latent heat of fusion of PCM samples are getting reduced. TGA thermographs are used to investigate the thermal stability of the composite PCM samples. TGA curves show that loss of mass happens above the operating temperature, and it is varied with different mass ratios of EG. Characterization of the prepared composite PCM samples is compared and found that PEG1000-85%/EG-15% is the best form-stable PCM, suitable for cooling the solar PV panel as well as to improve the electrical efficiency coupled with a decrease of temperature in the range of 35 °C to 40 °C. [ABSTRACT FROM AUTHOR]

Thermal energy storage is one of the most important strategies for sustainable development. Phase change materials (PCMs) can store thermal energy through an economically feasible and eco-friendly way. Herein, we develop a novel solid–solid phase change materials (SSPCMs) based on solvent-free radical polymerization of methyl methacrylate with methacrylate-functionalized polyethylene glycol (PEG). PEG featuring as phase change ingredient is tightly bonded with reliable crosslinking network, which offers the prepared solid–solid phase change materials (SSPCMs) with robust physical properties and good shape-stable properties. The chemical structures, microstructures, crystalline properties and thermal properties of the synthesized SSPCMs are, respectively, characterized by Fourier transform infrared spectroscopy, scanning electron microscope (SEM), X-ray diffraction, polarizing optical microscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). Accelerated thermal cycling test and leakage test are also conducted to illustrate the thermal reliabilities and shape-stable properties. Microphase separation is observed and discussed in SEM analysis. DSC results show that SSPCMs have reversible thermal storage capacities and their phase change enthalpies are related to the concentration of PEG content. TG and accelerated thermal cycling test explain the excellent thermal stability and reliability of SSPCMs. Therefore, the prepared SSPCMs with satisfied properties have potential in room-temperature-use thermal energy storage applications such as buildings, textile industry and so on. [ABSTRACT FROM AUTHOR]

Using palmitic acid (PA), expanded graphite (EG), and carbon fiber (CF) as raw materials, PA/EG/CF composite phase change materials (CPCMs) with diverse CF contents were invented by melt blending approach. The effects of different ratios on thermal properties were studied by experimental characterization and testing. Scanning electron microscopy images displayed that PA was adsorbed in the pores of the EG surface, while CF was disorderly but uniformly embedded in the interior and surface of pores. The chemical stability and thermal decomposition stability of CPCM at low temperature were proved by Fourier transform infrared spectrometer and thermogravimetric analyzer results, respectively. According to the law of heat storage/release time and latent heat variation, the optimal ratio scheme was determined, and its heat storage/release time was 65% and 59% lower than pure PA, respectively. The form-stable materials were prepared by compression forming method, and thermal cycling experiment results demonstrated that the higher the content of CF, the stronger the inhibition of mass loss. Based on the experimental results, the PA/EG/CF CPCM has the advantages of stable phase transition, strong stability, and fast heat storage and release rate, so it has a marvelous application prospect in the field of low-temperature heat storage engineering. [ABSTRACT FROM AUTHOR]

A novel composite of SrCO3-microencapsulated palmitic acid (PA) (PA@SrCO3 microcapsules) was prepared an evaluated as a phase-change material through a self-assembly approach. Samples of the material were studied by Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometery (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to determine the composition, crystalloid phase, microstructure, and morphology of the product. Also differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to monitor the thermal behavior of the PA@SrCO3 microcapsules. The data obtained through XRD and FTIR indicated the presence of characteristic peaks of PA and SrCO3, which is only possible when the species do not chemically react with each other. SEM images indicated the PA@SrCO3 microcapsules to be spheres with rough surfaces and average diameters of 1.5–2 µm. TEM images proved the samples as being composed of PA cores encapsulated in a SrCO3 coating. The DSC results showed that the samples had phase-change behaviors, similar to those of pristine PA (melting point = 66.9 °C, latent melting heat = 48.8 J g−1, freezing point = 55.7 °C, latent freezing heat = 43.2 J g−1, at a microencapsulation ratio of 43.92%), and TGA results showed improvements in the thermal stability of PA@SrCO3 microcapsules as opposed to PA, due to the presence of the SrCO3 shell. [ABSTRACT FROM AUTHOR]

The polyethylene glycol/wood-flour (PEG/WF) composites were synthesized as novel form-stable phase change materials (PCMs) using PEG as phase change material and WF as supporting material. The composite products were investigated by Fourier-transform infrared spectrometer, scanning electron microscopy (SEM), the leakage test, X-ray diffraction (XRD), differential scanning calorimeter (DSC), accelerated thermal cycling testing and thermogravimetry analysis (TG), respectively. The results revealed that the maximum latent heats and encapsulation ratio of the synthesized PEG/WF composite form-stable PCMs can reach 90.9 J g−1 and 52.8%, respectively. SEM images demonstrated that the porous tubular-like channel spaces of WF are completely blocked by PEG. The thermal cycling test showed that the synthesized PEG/WF composite form-stable PCMs have superior thermal reliability after 200 melting and freezing cycles without leakage. Additionally, TG results revealed that the prepared PEG/WF composite form-stable PCMs have good thermal stability with the decomposition temperature higher than 200 °C. Thus, the novel PEG/WF composite form-stable PCMs are a promising candidate using in wallboard and building materials due to its excellent thermal properties and thermal reliability. [ABSTRACT FROM AUTHOR]

In this work, the effect of rare-earth dysprosium oxide (Dy2O3) on the thermal stability properties of adipic acid (AA) matrix was investigated in detail. The AA/Dy2O3 composites were prepared by melting and mixing method. The microstructure, phase composition and thermal properties of AA/Dy2O3 composites were characterized by scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy and differential scanning calorimeter, respectively. It was found that there was a gradual change in melting temperature and latent heat of fusion after 1000th thermal cycles and the thermal stability of AA can be enhanced by incorporation of Dy2O3. The obtained AA doped with 3.0 mass% dysprosium oxide exhibited a small decline of only 3.2% in the melting latent heat after 1000th cycling tests compared with the decline of 13.7% for pure AA. In addition, the phase transition temperature was 142.1 °C with 227.9 J g−1 in the latent heat of fusion by adding 3.0 mass% dysprosium oxide after 1000th melting/freezing cycles. There was no chemical reaction between AA and Dy2O3 phase during the melting/freezing process, and the AA showed no obvious change in the structures after 1000th melting/freezing cycles. The Dy2O3 particles exhibited a homogenous dispersion in the AA matrix even after 1000th melting/freezing cycles. [ABSTRACT FROM AUTHOR]

This study reports the results of microstructure and thermal analysis of low-melting Bi–In alloys with potential for commercial application in the field of phase change materials. Three eutectic alloys Bi–47.44In, Bi–66.33In, Bi–77.92In (all in at.%) were prepared and investigated by means of scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometry (EDS) and differential scanning calorimetry (DSC). Microstructure of the prepared eutectic alloys was analysed using SEM–EDS, and identification of co-existing phases was done. Melting temperatures and latent heats of eutectic melting were measured using DSC technique. Experimentally obtained results were compared with the results of thermodynamic calculation according to CALPHAD (calculation of phase diagram) method, and good mutual agreement was noticed. [ABSTRACT FROM AUTHOR]

The thermo-physical properties of NaNO3/KNO3 (solar salt) added with Al2O3 and TiO2 nanoparticles as phase change material in thermal energy storage system were investigated. Initially the Al2O3 and TiO2 nanoparticles were added to NaNO3/KNO3 (60:40) with a concentration of 1%, 3% and 5 mass% using low-energy ball mill. The differential scanning calorimetry instrument is used to measure the thermal properties of the prepared PCM composites. It is found that the phase change temperature and latent heat capacity vary with Al2O3 and TiO2 nanoparticles loading levels. When the loading is not over 3 mass% of Al2O3, the phase change temperature drops, and the latent heat capacity increases up to 23.3%. When the loading is over 3 mass% of Al2O3, the phase change temperature increases, and the latent heat capacity drops to 14.23%. A significant increase in latent heat capacity is found around 3 mass% of Al2O3 loading. When the TiO2 nanoparticle concentration increases, the phase change temperature decreases, and the latent heat capacity increases up to 32.2%. When the TiO2 nanoparticle's concentration decreases, the phase change temperature increases, and the latent heat capacity decreases. The thermal conductivity of the composites was found to increase with the increase in the loading of nanoparticles. After adding 3% by mass of Al2O3 and TiO2 nanoparticles, the thermal conductivity was found to increase by 8.30 and 8.10%, respectively. From the characterization studies, we found that TiO2 helps to achieve the improved thermo-physical properties and heat storage characteristics for NaNO3/KNO3 which suggests their potential candidate of usage in the thermal energy storage system. [ABSTRACT FROM AUTHOR]

The microencapsulated myristic acid with titanium dioxide (TiO2) shell as shape-stabilized thermal energy storage materials was prepared using sol–gel method. The XRD and FT-IR techniques results presented that characteristic peaks of both myristic acid and TiO2 can be observed in the microencapsulated myristic acid with TiO2 shells. The phase change temperature, latent heat and thermal stability were investigated by a differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). According to these results, the melting and freezing temperatures of the MPCM/TiO2 shell and MPCM/TiO2 shell–fly ash are 56.95 and 52.22 °C; 47.56 and 26.68 °C and the latent heats of melting and freezing are 96.64 kJ kg−1; 97.72 and 23.43 kJ kg−1; and 22.57 kJ kg−1, respectively. TGA results certified that the addition of fly ash improved thermal stability. In particular, MPCM/TiO2 shell displays good thermal reliability after 1000 repeated melting/freezing cycling. [ABSTRACT FROM AUTHOR]

Shape-stabilized composite phase change materials composed of sebacic acid (SA) and MCM-41 were prepared by a facile blending and impregnating method. Various characterization techniques were carried out to characterize their structural and thermal properties, including thermogravimetry (TG) analyses and differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy. The XRD and FT-IR results indicated the interactions between SA and MCM-41, such as the capillary force and the hydrogen bonding, resulting in the confined crystallization process. As a result, the SA that was confined was amorphous. The TG analysis results showed that the presence of MCM-41 practically resulted in an overlapping of the two decomposition stages. The DSC analysis demonstrated that a decrease in the SA content was accompanied by a continuous decrease in the melting point and phase change enthalpy of the composites. [ABSTRACT FROM AUTHOR]

Current Al alloys still have shortcomings in their volumetric latent heat (LHV), compatibility and high-temperature inoxidizability, which limit their applications in the field of latent heat energy storage (LHES). The performance of aluminum alloys can be improved by the addition of Cu. The effects of the Cu content on the phase change temperature, mass latent heat (LHM), LHV, supercooling degree and microstructure of Al-Cu alloys were first studied by means of power-compensated differential scanning calorimetry, density, composition analysis and metallographic analysis. The measured values of the latent heat of Al-Cu alloys have been compared with the theoretically predicted values. The results show that for Al-Cu alloys with 7.3-52.8% Cu, the melting/freezing temperature is 540-655 °C/510-637 °C; the LHM and the LHV are 290-340 J g and 877-1224 J cm, respectively; and the degree of supercooling is within 10 °C. The LHM and LHV of Al-Cu alloys decrease with the increase in the Cu content; when the content of Cu is over 16.6%, the difference between the theoretical value of the LHM and the measured average of the Al-Cu alloys is within 5%. The LHES phases in Al-Cu alloys are the α-Al and theta phases. Quantitative relationships of the Cu content and metallurgical microstructure with the LHM and LHV of Al-Cu alloys are established, and both theoretical and empirical equations are obtained for the estimation of the latent heat for Al-Cu alloys. [ABSTRACT FROM AUTHOR]

Decanoic acid/expanded graphite composite phase change materials (DA/EG-PCMs) with high stability and excellent thermal conductivity were fabricated by blending expanded graphite (EG) and decanoic acid (DA). The structure, thermo-physical properties, and the formation mechanism of DA/EG-PCMs were investigated. The obtained results demonstrate that EG exhibits a network-like porous structure, which is superimposed of 10-50 μm thick graphite sheet. Therefore, DA can be effectively encapsulated through the binding between micropores and the surface adsorption of EG resulting in a relatively smaller DA/EG-PCMs particle with better dispersibility. In addition, adding EG into DA also increased both the thermal stability and the thermal conductivity while decreasing the charging and discharging time, which resulted in improved thermal efficiencies. Although adding EG can negatively influence the phase change behavior of DA, the temperature and enthalpy of phase change were still as high as 34.9 °C and 153.1 J g, respectively. Based on a combination of experimental results and a comprehensive analysis of the phase transformation kinetics, it is concluded that DA/EG-PCMs with 10 mass% EG with improved thermal properties can meet the requirements for efficient temperature control in low-to-medium environments. [ABSTRACT FROM AUTHOR]

In this study, a series of binary mixtures of N-butyl stearate (nBS) and methyl palmitate (MP) were used to produce a novel composite phase change material (CPCM) for potential application in the eastern China, and their thermal properties were investigated by differential scanning calorimetry (DSC). The results of DSC indicated that the mixture consisting of 10 mass% nBS and 90 mass% MP is optimum as the CPCM in terms of the phase change temperature ranges ( T = 19.74-5.59 °C; T = 18.34-33.80 °C) and latent heats (Δ H = 176.8 J g; Δ H = 189.3 J g). On the other hand, the thermal reliability and chemical stability of the CPCM after 120, 180, 240, 300, 360 and 500 accelerated thermal cycling tests were studied by DSC and fourier transform infrared (FTIR) analysis. The results demonstrated that the CPCM had good thermal reliability and chemical stability. [ABSTRACT FROM AUTHOR]

Polyethylene glycol (PEG)/active carbon granule (ACG) and/or expanded graphite (EG) composite as a shape-stabilized phase change materials (PCMs) were firstly prepared by a melt blending via novel dynamic impregnating method which can be applied to air conditioning system in the middle of the heat medium, radiant cooling systems, etc. Various characterization techniques including X-ray diffraction, scanning electron microscope, differential scanning calorimeter, thermal gravimetry (TG) and thermal conductivity were performed to investigate the crystalline and thermal properties of the PCMs. The results indicated that phase change temperatures and enthalpies were decreased as the mass percentage of PEG was decreased. The crystallinity of PEG in the PCMs decreased with the increase in the ACG and/or EG content. And, the TG and thermal conductivity results showed that the thermal conductivity of PEG-based PCMs could be improved when ACG and/or EG was introduced. Interestingly, compared to PEG/ACG PCMs, the PEG/EG PCMs had higher crystallinity, better thermal conductivity. A reasonable physical model was also established to analyze the packing theory for PEG/ACG and/or PCM/EG PCMs. Notably, this study will provide an novel and efficient fabrication method of shape-stabilized polymer-based PCMs for heat storage application. [ABSTRACT FROM AUTHOR]

This study deals with fabrication, thermal properties and thermal reliabilities of microencapsulated paraffin by suspension-like copolymerization of ethyl methacrylate (EMA) with acrylic acid (AA) and styrene (St). Trimethylolpropanetriacrylate (TMPTA) was employed as crosslinking agents. The microencapsulated phase change materials (MicroPCMs) were characterized by using scanning electron microscopy (SEM), differential scanning calorimetry and thermal gravimetric analysis (TG). The microcapsule with P(EMA-co-AA-co-St-co-TMPTA) copolymer as shell exhibits higher phase change enthalpies of melting (117.8 J g) and crystallization (115.3 J g) compared with the microcapsule with P(EMA-co-AA-co-TMPTA) copolymer. TG analysis demonstrated that the thermal resistant temperatures of these two MicroPCMs were increased by more than 10 °C compared with the raw paraffin. The PCMs content of these two MicroPCMs dropped by <6 % after 1000 thermal cycling. Thermal images showed that the foam with microcapsule exhibits an upgraded thermal regulation capacity. As a consequence, microcapsules with EMA-based copolymer possess good potentials for thermal energy storage and thermal regulation. [ABSTRACT FROM AUTHOR]

Based on the theory calculation, the capric-palmitic-stearic (CA-PA-SA) ternary eutectic mixture was prepared with melting and freezing temperature of 19.93 and 16.84 °C, respectively. Regarding CA-PA-SA as phase change materials (PCMs), and activated carbon (AC) as the additive, the CA-PA-SA/AC composites can be prepared by physical blend method which can be applied to high-temperature cooling application in solar cooling systems, radiant cooling systems, etc. A comprehensive study of the structure, thermal properties, thermal stability, thermal durability and thermal storage-release characteristic of CA-PA-SA/AC composites was conducted through the FT-IR, DSC, TG, accelerated thermal cycling test and melting-freezing experiments. The results show that, with the increase in AC content, the melting temperature of CA-PA-SA/AC composites decreases gradually, whereas the freezing temperature increases. And the addition of AC can enhance the thermal stability, the thermal durability and the thermal storage-release rate of PCM: the thermal stability of PCM1-PCM4 is much greater than that of pure mixture, and its storage time was reduced by 37, 31, 23 and 9 %, respectively, while its release time was reduced by 67, 58, 48 and 43 % respectively. [ABSTRACT FROM AUTHOR]

Stearic acid/diatomite composite form-stable phase change materials (PCMs) have been prepared by using a direct impregnation method without vacuum treatment. The surface morphology, chemical compatibility, thermal properties and thermal stability were characterized by scanning electron microscopy, Fourier transform infrared spectrometer and X-ray diffraction (XRD), differential scanning calorimeter and thermogravimetric analysis (TG), respectively. The results show that there are only physical interactions between stearic acid and diatomite in composite PCM. XRD analysis reveals that crystal type is not affected by composite technology of SA/diatomite composite form-stable PCM with decrease in crystal size due to the limited pores in diatomite. The melting and freezing temperatures of stearic acid/diatomite composite, respectively, are 52.3 and 48.4 °C. The latent heat of SA/diatomite composite reaches 57.1 J g, potential to be used in a practical application. TG result indicates that the decomposition of SA/diatomite composite starts at 192 °C, implying that the SA/diatomite has a good thermal stability. [ABSTRACT FROM AUTHOR]

This study focuses on the preparation of camphene/palmitic acid mixture as novel phase change material for the first step of composite-based phase change materials. Camphene-palmitic acid-based composite phase change materials (PCMs) for thermal energy storage were prepared by vacuum impregnation method. The maximum incorporation percentage for camphene-palmitic into pyroclastic, fly ash, barite and marble powder were found to be 33.09, 55.5, 31.5 and 35.96 %, respectively. The differential scanning calorimetry analysis revealed that the composite PCMs were suitable applicants for building applications in terms of their appropriate phase change temperatures and extensive latent heat values. The SEM results showed that the homogeneity of the samples is good, and according to supporting materials porosity formation is observed. Thermal cycling test indicated that the form-stable composite PCMs have good thermal reliability and chemical stability although they were subjected to 2,000 melting/freezing cycling. [ABSTRACT FROM AUTHOR]

This study focused on preparation and thermal properties of poly(stearyl methacrylate) shell (PSMA) microcapsules containing n-octadecane as a phase change material (PCM). Pentaerythritol triacrylate (PETA) and divinylbenzene (DVB) were employed as crosslinking agents. The surface morphologies, particle sizes, and distributions of the microencapsulated phase change material (microPCM) were studied by scanning electron microscopy. The thermal properties, thermal reliabilities, and thermal stabilities of the microPCMs were investigated by differential scanning calorimetry and thermal gravimetric analysis. The microPCM with DVB exhibits higher phase change enthalpies of melting (87.9 J g) and crystallization (94.8 J g) and a greater thermal stability in comparison with the microPCM with PETA. The phase change temperatures and enthalpies of the microPCMs varied little after thermal cycles. Thermal images showed that the gypsum board with PSMA/ n-octadecane microPCM possessed temperature-regulated property. Therefore, microencapsulated n-octadecane with PSMA as shell has good thermal energy storage and thermal regulation potential. [ABSTRACT FROM AUTHOR]

Epoxy resins are well-known materials that show beneficial properties, such as high tensile strength and modulus, good adhesive properties, low cost, and ease of processing and environmental advantages. However, epoxy resin adhesive has no characteristic of thermal storage. Latent heat storage is one of the favorable kinds of thermal energy storage methods considered for energy saving and thermal efficiency in various fields, such as solar air conditioning systems and buildings. So we prepared thermal-enhanced epoxy resin adhesive by using PCM. This paper addresses the effects of n-hexadecane and sodium lauryl sulfate on the thermal properties and chemical properties of epoxy resin adhesive and HEAC, using differential scanning calorimetry, thermal gravimetric analysis, and Fourier transform-infrared spectroscopy. Also, we evaluated the applicability of composite epoxy resin adhesive to wood-based flooring using n-hexadecane, through measurement of bonding strength from universal testing machine analysis. [ABSTRACT FROM AUTHOR]

In the present work, a novel PAN-based form-stable composite phase change materials with the methyl stearate (MES) encapsulated in the supporting matrices of polyacrylonitrile (PAN) nanofibers were fabricated through electrospunning for the storage and retrieval of thermal energy. Influences of graphene oxide (GO) addition on the chemical properties, structural morphologies, mechanical properties, thermal energy storage properties, thermal stability, and thermal energy storage/retrieval rates of electrospun MES/PAN/GO phase change composite nanofibers were systematically investigated by FT-IR, FE-SEM, tensile testing, DSC, TG, and measurement of melting/freezing times, respectively. The results revealed that the incorporation of GO effectively enhanced the mechanical properties, thermal stability, as well as heat storage and release rates of the phase change composite nanofibers. The averaged tensile strength of electrospun MES/PAN/GO phase change composite nanofibers increased significantly by 573 % with 10 mass% loading of GO, while elongation at break had a maximum 107 % increment when adding 3 mass% of GO. The DSC results indicated that the electrospun PAN-based phase change composite nanofibers with various GO loadings had suitable phase transition temperatures with the latent heat ranging from about 92 to 109 kJ kg and exhibited good thermal reliability in terms of DSC measurements during 50 melting-freezing cycles. Moreover, the melting and freezing time were significantly decreased about 44 and 43 % for the MES/PAN/GO5, as well as 59 and 64 % for the MES/PAN/GO10 after introducing the GO into the composite nanofibers systems. [ABSTRACT FROM AUTHOR]

Form-stable phase change materials (PCMs) with high thermal conductivity are essential for thermal energy storage systems, which in turn are indispensible in solar thermal energy applications and efficient use of energy. In this paper, a new palmitic acid (PA)/polyaniline (PANI) form-stable PCMs were prepared by surface polymerization. The highest loading of PA in the form-stable PCMs was 80 mass% with the phase change enthalpy (Δ H) of 175 J g. Copper nanowires (Cu NWs) were introduced to the form-stable PCM by mixing the Cu NWs with PA and ethanol prior to the emulsifying of PA in surfactant solution. The Cu NWs would remain intact in case the ethanol was eliminated before the PA/Cu NWs mixture was mixed with surfactant solution. Otherwise, the Cu NWs would be partially oxidized under the attack of ethanol and ammonium persulfate. The Δ H of the form-stable PCMs containing Cu NWs decreased linearly with the increasing of Cu NWs loading. The Δ H of the form-stable PCMs doped with 11.2 mass% Cu NWs was 149 J g. The thermal conductivity of the form-stable PCMs could be effectively improved by Cu NWs. By adding 11.2 mass% Cu NWs, the thermal conductivity of the form-stable PCM could attain 0.455 W m K. [ABSTRACT FROM AUTHOR]

In this study, CaCl·6HO/expanded graphite (EG) composite was prepared as a novel form-stable composite phase change material (PCM) through vacuum impregnation method. CaCl·6HO used as the PCM was dispersed by surfactant and then, was absorbed into the porous structure of the EG. The surfactant was used to enhance the bonding energy between CaCl·6HO and EG, which fulfilled the composites with good sealing performance and limited the leakage of the inside CaCl·6HO. Differential scanning calorimetry and thermal gravimetric analysis show that all the composite PCMs possess good thermal energy storage behavior and thermal stability. Thermal conductivity measurement displays that the conductivities of the samples have been significantly improved due to the highly thermal conductive EG. The thermal conductivity of the sample including 50 mass% CaCl·6HO (8.796 W mK) is 14 times as that of pure CaCl·6HO (0.596 W mK). Therefore, the obtained composite PCMs are promising for thermal energy storage applications. [ABSTRACT FROM AUTHOR]

The thermal properties of paraffin as phase change material (PCM), combined with layered zinc hydroxide nitrate (LZHN) and intumescent flame retardant (IFR), have been studied by thermogravimetric analysis (TG), TG-Fourier transform infrared spectrometry (TG-FTIR), cone calorimeter (CONE),and differential scanning calorimetry (DSC). The TG results indicated that the thermal stabilities of the paraffin and paraffin/IFR composites could be improved when dodecyl sodium sulfate-modified LZHN (ds-LZHN) was incorporated. The TG-FTIR results indicated that ds-LZHN could reduce the release of combustible gases for paraffin and paraffin/IFR. The CONE results showed that the flame-retardant efficiency of IFR could be improved in the paraffin/IFR system owing to ds-LZHN. DSC results presented that the phase change temperatures and latent heats of the composites were determined by the dispersed paraffin with their mass percentage. [ABSTRACT FROM AUTHOR]

A series of fatty acids/carbon nanotubes (CNTs) composite shape-stabilized PCMs were prepared through infiltration method by using the eutectic mixture of capric acid, lauric acid, and palmitic acid as phase change materials, multi-walled CNTs as a supporting material. Nitrogen adsorption-desorption curves and SEM images of composite shape-stabilized PCMs indicate that the eutectic mixture was effectively absorbed into the porous structure of the CNTs. DSC thermograms show that the composite fatty acids/CNTs possess good phase change behavior. And the latent heat of the sample absorbed with 80 wt% fatty acids can achieve 101.6 J g in the melting process and its phase change temperatures and latent heat almost remain unchanged in 30 times of thermal cycling. Moreover, the thermal conductivity of the composite materials are significantly improved (up to 0.6661 W m k) due to the addition of the highly thermal conductive CNTs. [ABSTRACT FROM AUTHOR]

Graphite/ n-docosane composite phase change materials (PCM) were prepared. 4, 10, and 16% graphite were added into n-docosane in order to study the effect of the amount of graphite to the thermal properties of the composite PCM. The structure of the composite PCM was characterized using scanning electron microscopy. The thermal properties of the composite PCM were determined using thermal constant analysis, heat storage/release curve, differential scanning calorimetry, and thermogravimetry analysis. The results revealed that the heat storage/release rate and the thermal conductivity increased with an increase in the amount of graphite, whereas the latent heat of the composite PCM decreased with the increase in the amount of graphite. [ABSTRACT FROM AUTHOR]

A series of PA-TD mixtures were prepared and their thermal properties were studied by DSC and thermal conductivity measurement. The phase diagram of the binary system was constructed, which showed an eutectic behavior for the solid-liquid equilibrium line. The eutectic composition of the binary system was at the mass fraction of TD near 0.7 with an eutectic temperature of about 29°C. At TD side, PA was partially miscible in the TD solid matrix and the solid phase transition of TD had an effect on the solidus line. The eutectic composition mixture could be viewed as a new phase change material with large thermal energy storage capacity. [ABSTRACT FROM AUTHOR]