Characterization and effects of thermal cycling on the properties of paraffin/expanded graphite composites

Wang, Qingqing; Zhou, Dan; Chen, Yuming; Eames, Philip C.; Wu, Zhiming

doi:10.1016/j.renene.2019.09.091

Cited by 94 publications

(20 citation statements)

References 29 publications

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“…To solve the low thermal conductivity of paraffin, many thermally conductive fillers have been introduced, such as metal foam, [ 19 ] expanded graphite, [ 20‐22 ] graphene oxide, [ 23,24 ] carbon nanotube, [ 25,26 ] mesoporous silica, [ 27,28 ] and so on. Hexagonal boron nitride (h‐BN) has superior thermal conductivity, electrically insulating, outstanding oxidation resistance, excellent corrosion resistance, and remarkable dielectric properties.…”

Section: Background and Originality Contentmentioning

confidence: 99%

Preparation and Thermal Properties of Shape‐stabilized Paraffin/ NPGDMA/BN Composite for Phase Change Energy Storage

Chen

Han

et al. 2020

Chin. J. Chem.

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of main observation and conclusion Paraffin, as an excellent phase change material (PCM), is limited by the leakage problem and low thermal conductivity. In this research, a novel paraffin/neopentyl glycol dimethacrylate/boron nitride (paraffin/NPGDMA/BN) composite PCM was successfully prepared via a physical mixing process. NPGDMA in paraffin/NPGDMA/BN composite PCM was cured by UV light under the action of photo initiator, which can improve the shape stability to avoid the leakage of paraffin in the process of phase change. By comparing the leakage rate, latent heat, and thermal conductivity, the optimal mass ratio of paraffin and NPGDMA was selected to be 7 : 3. It was showed that the presence of 5 wt% BN led to increasing in thermal conductivity by up to 59%. The microstructure of the composite PCMs was characterized by SEM, FTIR, and XRD. The composite PCMs can be processed into a variety of shapes by using molds. The paraffin/NPGDMA/BN composite PCM exhibited a significantly improved shape stability and large phase change enthalpy of 123.0 J/g. The leakage rate of paraffin/NPGDMA/BN was much improved after being soaked with petroleum ether.

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Section: Background and Originality Contentmentioning

confidence: 99%

Preparation and Thermal Properties of Shape‐stabilized Paraffin/ NPGDMA/BN Composite for Phase Change Energy Storage

Chen

Han

et al. 2020

Chin. J. Chem.

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“…Parafin memiliki sifat yang lebam (inert) dan stabil di bawah suhu 500 o C. Selain itu, parafin tidak mengalami perubahan volume yang signifikan ketika mencair dan memiliki tekanan uap yang relatif rendah ketika dalam bentuk cair [9]. Berdasarkan karakterisitik tersebut, maka sistem yang menggunakan parafin sebagai PCM biasanya mengalami siklus padat-cair yang panjang [10].…”

Section: Pendahuluanunclassified

Pemanfaatan material fasa berubah untuk mempertahankan kesegaran sayuran

Irsyad

Tobing

Susila

2020

Turbo

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Indonesia is an agricultural country with a tropical climate. One of the many agricultural products in Indonesia is vegetables. Handling of vegetables after harvesting is important because the decrease in product quality can reach up to 50%. This decrease in quality is the result of metabolic processes such as transpiration and respiration that occur in post-harvest vegetables. The respiration rate of vegetables cannot be stopped but can be slowed down by lowering the temperature, so that the freshness of the vegetables can last longer. One method of maintaining the temperature of vegetables is storage in a cool box with cooling media. Phase change material (PCM) is an alternative cooling medium that utilizes latent heat in thermal energy storage. Paraffin is a PCM that can be used for this application. Paraffin has a freezing and melting temperature range that can be adjusted according to your needs, namely by mixing liquid paraffin and solid paraffin. This study used mixed paraffin with a liquid-solid paraffin ratio of 98:2 mass basis. This mixture has a melting temperature of 6 o C until 13 o C and is close to the optimal temperature for storing vegetables, which is 5 o C. In this study, testing was also carried out using water as a comparison. The test results show that ice can make vegetables last longer in cold conditions, namely that it is able to maintain the vegetable temperature below 20 o C for 11 hours, while paraffin only lasts 2 hours. The physical condition of the vegetables that are cooled with ice in the packing changes color and becomes watery because the water in the vegetables is condensed. Meanwhile, on cooling with paraffin it is physically fresher.

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“…Based on the findings of these authors, the mechanical properties of BFRPs were firstly improved; however, after 40 cycles, cracks nucleated and delamination occurred due to mismatch in CTE of fibers and formation of matrix microcracks. Wang et al [15] investigated the effect of thermal cycling on the properties of paraffin/expanded graphite composites. They also added a suitable proportion of expanded graphite (EG) into the paraffin, to enhance the heat-transfer rate and improve the thermal efficiency of the whole heat-storage system.…”

Section: Introductionmentioning

confidence: 99%

Thermal Shock Behavior of Twill Woven Carbon Fiber Reinforced Polymer Composites

2021

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In the current research, the effect of cyclic temperature variation on the mechanical and thermal properties of woven carbon-fiber-reinforced polymer (CFRP) composites was investigated. To this, carbon fiber textiles in twill 2/2 pattern were used as reinforced phase in epoxy, and CFRPs were fabricated by vacuum-assisted resin-infusion molding (VARIM) method. Thermal cycling process was carried out between −40 and +120 °C for 20, 40, 60 and 80 cycles, in order to evaluate the effect of thermal cycling on mechanical and thermal properties of CFRP specimens. In this regard, tensile, bending and short beam shear (SBS) experiments were carried out, to obtain modulus of elasticity, tensile strength, flexural modulus, flexural strength and inter-laminar shear strength (ILSS) at room temperature (RT), and then thermal treated composites were compared. A dynamic mechanical analysis (DMA) test was carried out to obtain thermal properties, and viscoelastic properties, such as storage modulus (E’), loss modulus (E”) and loss factors (tan δ), were evaluated. It was observed that the characteristics of composites were affected by thermal cycling due to post-curing at a high temperature. This process worked to crosslink and improve the composite behavior or degrade it due to the different coefficients of thermal expansion (CTEs) of composite components. The response of composites to the thermal cycling process was determined by the interaction of these phenomena. Based on SEM observations, the delamination, fiber pull-out and bundle breakage were the dominant fracture modes in tensile-tested specimens.

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Characterization and effects of thermal cycling on the properties of paraffin/expanded graphite composites

Cited by 94 publications

References 29 publications

Preparation and Thermal Properties of Shape‐stabilized Paraffin/ NPGDMA/BN Composite for Phase Change Energy Storage

Preparation and Thermal Properties of Shape‐stabilized Paraffin/ NPGDMA/BN Composite for Phase Change Energy Storage

Pemanfaatan material fasa berubah untuk mempertahankan kesegaran sayuran

Thermal Shock Behavior of Twill Woven Carbon Fiber Reinforced Polymer Composites

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