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Microencapsulated phase change materials (MicroPCMs) can be incorporated into a traditional thermal insulation material, such as a foam, to form a new temperature-adaptable material. Polyurea/polyurethane (PU) as the encapsulating shell makes the MicroPCMs more compatible with the polyurethane foam matrix. This study focuses on increasing the thermal storage abilities and reliabilities of the PU-based MicroPCMs as well as improving the temperature-regulating properties of PU foams treated with these materials by incorporating lauryl methacrylate (LMA) and polyols into the MicroPCM particles. Paraffin was successfully microencapsulated by a PU/PLMA hybrid shell via staged polymerization of jointly using interfacial and suspension-like polymerization. PU foams integrating the as-prepared MicroPCMs were produced. The thermal storage abilities as well as working reliabilities of the MicroPCMs were improved when PLMA was introduced in the shells and were further enhanced when they were modified by polyols. The PU foams containing MicroPCMs with polyol-modified hybrid shells have better mechanical properties and temperature-regulating properties than do the foams containing MicroPCMs with unmodified shells. In conclusion, MicroPCMs with polyol-modified PU/PLMA hybrid shells possess promising application prospects for energy efficient buildings and advanced cold-chain logistics systems. [ABSTRACT FROM AUTHOR]

This paper was aimed to prepare, characterize and determine the comprehensive evaluation of promising composite macrocapsules containing microencapsulated PCMs (phase change materials) with calcium alginate gels as the matrix material. Macrocapsules containing microcapsules were fabricated by piercing-solidifying incuber method. Two kinds of microcapsules with n-tetradecane as core material, UF (urea-formaldehyde) and PMMA (poly(methyl methacrylate)) respectively as shell materials were prepared initially. For application concerns, thermal durability and mechanical property of macrocapsules were investigated by TGA (thermal gravimetric analysis) and Texture Analyser for the first time, respectively. The results showed excellent thermal stability and the compressive resistance of macrocapsules was sufficient for common application. The morphology and chemical structure of the prepared microcapsules and macrocapsules were characterized by SEM (scanning electron microscopy) and FT-IR (fourier transform infrared) spectroscopy method. Phase change behaviors and thermal durability of microcapsules and macrocapsules were investigated by DSC (differential scanning calorimetry). In order to improve latent heat of composite microcapsules, the core-shell weight ratio of tetradecane/UF shell microcapsules was chosen as 5.5:1 which obtained the phase change enthalpy of 194.1 J g −1 determined by DSC. In conclusion, these properties make it a feasible composite in applications of textile, building and cold-chain transportation. [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]

Microcapsules containing n -octadecane with different n -butyl methacrylate (BMA)-based copolymer shells were fabricated by a suspension-like polymerization method. n -butyl acrylate (BA), methacrylic acid (MAA) and acrylic acid (AA) were employed as monomers to copolymerize with BMA. The surface morphologies of the microencapsulated phase change materials (MicroPCMs) were studied by scanning electron microscopy (SEM). The thermal properties, thermal reliabilities and thermal stabilities of the MicroPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The temperature-regulated properties of the MicroPCMs were determined by an infrared thermography. The incorporation of MAA or AA to the acrylic composition of the polymer shells led to an increase in both the heat storage capacities and thermal stabilities of the MicroPCMs. The MicroPCMs with P(BMA-co-MAA) exhibit a greater heat capacity and thermal stability compared with the MicroPCMs with P(BMA-co-AA). The MicroPCMs with P(BMA-co-MAA) have the highest latent heats of melting (144.3 J/g) and crystallization (152.9 J/g) as well as the highest thermal resistant temperature (249 °C). The phase change temperatures and enthalpies of the MicroPCMs varied little after 1000 thermal cycles. Thermal images showed that the gypsum board containing the MicroPCMs with BMA-based copolymers as shells, especially with P(BMA-co-MAA) and P(BMA-co-AA) as shells, possessed temperature-regulated properties. As a result, the MicroPCMs with BMA-based copolymers as shells have good thermal energy storage and thermal regulation potentials, such as solar energy-saving building materials. [ABSTRACT FROM AUTHOR]

MicroPCMs (microencapsulated phase-change materials) were successfully synthesized using PMMA (poly(methyl methacrylate)) and UF (urea-formaldehyde) as raw materials for hybrid shells, and n -tetradecane as core materials. NMA ( n -methylol acrylamide) with two functional groups of double-bond and hydroxymethyl was used as a crosslinking agent. The morphologies and chemical structures of microPCMs were characterized using scanning electron microscopy (SEM) and Fourier transformed infrared (FTIR) spectroscopy. The agglomerations of the UF/PMMA hybrid samples might be influenced by two factors: cross linking action of NMA and PMMA/UF ratio in shell materials. The phase change properties and thermal durability were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), respectively. The UF/NMA/PMMA hybrid shell microcapsules has an enthalpy of 175.5 J/g which is higher than the single-layer shell samples of PMMA and UF, and a better leakproofness than the UF/PMMA hybrid samples without NMA owing to the semi-IPN microstructure. Likewise, the UF/NMA/PMMA hybrid samples have higher thermal durability than the single layer shell samples of PMMA and UF and the UF/PMMA hybrid samples without NMA. Moreover, the thermal cycling test of the UF/PMMA hybrid samples with NMA was carried out for 100 heating/cooling cycles and indicated that the developed hybrid shell microPCMs have good chemical stability and thermal reliability. The heating-up experiment revealed that the foam treated by microcapsules had a better thermoregulatory property than the raw foam. Based on the results obtained, it can be concluded that n -tetradecane/UF/PMMA microPCMs have potential thermal energy storage applications. [ABSTRACT FROM AUTHOR]

Due to the low direct thermal effect of solar irradiation, conventional phase-change microcapsules have poor solar energy utilization capability. To increase the solar-to-thermal energy storage efficiency, in this work, we reported a light-driven microencapsulated n-eicosane based on a crystalline TiO 2 shell coated by graphene oxide (GO)-based copper monosulfide (CuS) (CuS-GO) nanoconverter. Due to the combination of local surface plasma resonance (LSPR), semiconductor and synergetic effects, the CuS-GO nanoconverter conferred full-spectrum solar light-to-thermal conversion capability on the microcapsule system. The resultant n-eicosane@TiO 2 @CuS-GO microcapsules achieved high full-spectrum solar-to-thermal storage efficiency (97.1%) under stimulated solar light with no compromise of the latent heat density (212.0 ± 1.2 J/g). Furthermore, the thermal conductivity of n-eicosane@TiO 2 @CuS-GO (0.985 ± 0.004 W/(m·K)) significantly increased by 39.9% compared with that of n-eicosane@TiO 2. These results indicate that this light-driven microcapsule with superior properties is advantageous for direct solar-to-thermal energy utilization applications. Image 1 • CuS-GO nanoconverter encapsulated the microcapsules uniformly like a second shell. • The light-driven microcapsules exhibited full-spectrum absorption and conversion capability. • The solar energy storage efficiency was improved up to 97.1%. • The thermal energy storage capability of the microcapsules was 212.0 ± 1.2 J/g with high encapsulation ration (86.5%). [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrated salt was supported by superporous hydrogel (SPH) with graphene oxide (GO). • The energy storage efficiency increased by 43 % when the SPH with GO as a supporter. • SPH-supported form-stable phase change materials (FPCMs) possess temperature-regulated property. • The sponge-like structure resulted in over 140 % increase in the hardness of FPCMs. • The interconnected channels and the enhanced thermal conductive led to a 42 % decrease in time to charge energy. Hydrated salt-based form-stable phase change materials (FPCMs) with appropriate phase transition temperatures display great potentials in the thermal management of transport packaging. In this study, a series of novel hydrated salt-containing sponge-like FPCMs supported by superporous hydrogel (SPH) was fabricated through a foam polymerization method. N,O-carboxymethyl chitosan (CMCS) and graphene oxide (GO) were chosen as modifiers. The surfaces and inter structures of the FPCMs were examined by scanning electron microscopy (SEM) and optical microscopy (OM). Differential scanning calorimetry (DSC) was used to measure the thermal storage efficiencies of the FPCMs. The temperature responses and the temperature-regulation properties of the FPCMs were tested by a thermal conductivity measurement apparatus, a temperature recorder and an infrared thermography. The mechanical properties of the FPCMs were obtained by a texture analyser. DSC analysis demonstrates that the sponge-like FPCMs with teeming ionic groups can make them load and grasp more PCMs to acquire high energy storage efficiencies. The FPCM with GO&CMCS-modified SPH achieved the highest effective enthalpy percentage (87.8 %) and melting enthalpy (169.0 J/g), which was 43 % higher than that of nonsuperporous hydrogels (NSPH)-supported FPCM without CMC and GO. Meanwhile, the interconnected channels and the enhanced thermal conductivity of the GO-embedded FPCM with SPH led to a 42 % decrease in time to charge when compared with FPCM with NSPH. Besides, the hardness of FPCMs with SPH was remarkable enhanced by over 140 % comparing to FPCMs with NSPH since the internal pores of the SPH could absorb the impact energy. Moreover, the mechanical properties of the FPCMs were further improved when CMCS and GO were incorporated into the matrix. Additionally, thermal images show that the SPH-supported FPCMs, especially modified by CMCS and GO, exhibit a temperature-regulation property, which is beneficial in transport packaging for extending the time to discharge. As a result, the sponge-like FPCMs with embedded GO was an excellent candidate used for energy storage and thermal regulation in transportation. [ABSTRACT FROM AUTHOR]