The effects of nanoparticles on morphology and thermal properties of erythritol/polyvinyl alcohol phase change composite fibers

e-Polymers ◽  
2018 ◽  
Vol 18 (4) ◽  
pp. 321-329 ◽  
Author(s):  
Haishan Che ◽  
Qianqiao Chen ◽  
Qin Zhong ◽  
Si He
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Polyvinyl Alcohol ◽  
Phase Change ◽  
Phase Change Materials ◽  
Composite Fibers ◽  
Fiber Morphology ◽  
Shape Stability ◽  
Heat Loss Rate ◽  
High Enthalpy

AbstractErythritol (E)/polyvinyl alcohol (PVA) phase change composite fibers in which PVA acts as supporting material and different contents of erythritol act as phase change materials (PCMs) were prepared by electrospinning. The effects of different nanoparticles on fiber morphology and thermal properties of composites were also studied. The morphology and thermal properties were characterized by using scanning electron microscopy (SEM), differential scanning calorimetery (DSC) and a thermal conductivity test, respectively. The results showed E/PVA composite fibers were cylindrical with a smooth surface. The content of erythritol in composites could reach a high of 80 wt% with good shape stability, and a high enthalpy value of 258.9 J/g after 100 thermal cycles. The effects of nanoparticles on composites were mainly embodied in decreasing average fiber diameters (AFDs), phase change temperatures and enthalpies with the increase of particle concentrations, and improving fiber stability and thermal conductivity. Among them, the smallest AFDs (0.56 μm) and the lowest heat loss rate (1.0%) were obtained from composites with 4% nano C and 4% nano Al2O3, respectively. The 4% nano SiO2 composites possessed the best shape stability. In addition, the composites that contains 4% nano carbon could decrease the erythritol’s supercooling of 7.55°C, and showed the highest thermal conductivity of 1.55 W/m·K, which was 167% of E/PVA composites. These results demonstrate that E/PVA composites possess high enthalpy values while they improve shape stability and thermal conductivity.

Paraffin/carbon aerogel phase change materials with high enthalpy and thermal conductivity

2017 ◽  
Vol 25 (9) ◽  
pp. 512-518 ◽  
Author(s):  
Benqiang Tian ◽  
Wenbin Yang ◽  
Fangfang He ◽  
Changqiong Xie ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Carbon Aerogel ◽  
High Enthalpy

Thermal Properties and Morphology of Electrospun PEG/PVP Composite Fibers as Novel Phase Change Materials

2012 ◽  
Vol 204-208 ◽  
pp. 3998-4001
Author(s):  
Qi Song Shi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Phase Change ◽  
Phase Change Materials ◽  
Composite Fibers ◽  
Scanning Calorimetry ◽  
Ultrafine Fibers ◽  
Scanning Electron

The ultrafine fibers based on the composites of polyethylene glycol(PEG) and polyvinylpyrrolidone(PVP) were prepared successfully via electrospinning as phase change materials. The thermal properties and morphology of the composite fibers were studied by differential scanning calorimetry(DSC) and scanning electron microscopy(SEM), respectively.

scholarly journals Investigation of Thermal Properties of Novel Phase Change Material Mixtures (Octadecane-Diamond) with Laser Flash Analysis

2019 ◽  
Vol 26 (4) ◽  
pp. 211-218
Author(s):  
Mateusz Sierakowski ◽  
Wojciech Godlewski ◽  
Roman Domański ◽  
Jakub Kapuściński ◽  
Tomasz Wiśniewski ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Phase Change ◽  
Power Plants ◽  
Large Scale ◽  
Phase Change Materials ◽  
Heat Dissipation ◽  
Electronics Cooling ◽  
Diamond Powder ◽  
Heat Of Fusion

AbstractPhase change materials (PCMs) are widely used in numerous engineering fields because of their good heat storage properties and high latent heat of fusion. However, a big group of them has low thermal conductivity and diffusivity, which poses a problem when it comes to effective and relatively fast heat transfer and accumulation. Therefore, their use is limited to systems that do not need to be heated or cooled rapidly. That is why they are used as thermal energy storage systems in both large scale in power plants and smaller scale in residential facilities. Although, if PCMs are meant to play an important role in electronics cooling, heat dissipation, or temperature stabilization in places where the access to cooling water is limited, such as electric automotive industry or hybrid aviation, a number of modifications and improvements needs to be introduced. Investigation whether additional materials of better thermal properties will affect the thermal properties of PCM is therefore of a big interest. An example of such material is diamond powder, which is a popular additive used in abradants. Its thermal diffusivity and conductivity is significantly higher than for a pure PCM. The article presents the results of an analysis of the effect of diamond powder on thermal conductivity and diffusivity of phase change materials in the case of octadecane.

Study on Dispersion Stability Characteristics of TiO2 Nanoparticles in PCM for Use in Cold Storage Air-Conditioning

2019 ◽  
Vol 972 ◽  
pp. 159-164
Author(s):  
Xiao Yan Li ◽  
Xin Yue Miao
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Phase Change ◽  
Cold Storage ◽  
Air Conditioning ◽  
Phase Change Materials ◽  
Ultrasonic Time ◽  
Nanoparticles Concentration ◽  
Dispersion Condition ◽  
Nanocomposite Pcm

A new organic phase change materials (PCM) for cool storage was developed for use in cold storage air-conditioning. The thermal properties of the new organic PCM were measured with a differential scanning calorimeter (DSC). To improve the thermal conductivity of the new organic PCM, the further research of using nanocomposite technology to the organic PCM SSW-4 was made. The effects of nanoparticles concentration on dispersion, ultrasonic time and consistence of dispersant in the best ultrasonic time on the dispersion were investigated by experiment. The results showed that the thermal conductivity of the nanocomposite PCM TiO2 /SSW-4 increased by approximately 16.27% compared to that of the organic PCM SSW-4. The best dispersion condition of preparation for TiO2 /SSW-4 was confirmed.

The Experimental Research and Numerical Simulation on Thermal Properties of Molten Salt at Melting Point

2009 ◽  
Author(s):  
Yannan Liang ◽  
Jiemin Zhou ◽  
Ying Yang ◽  
Ye Wu ◽  
Yanyan He
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Phase Change ◽  
Molten Salts ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Phase Interface ◽  
Measuring System ◽  
Solid Liquid

The use of phase-change materials for latent heat storage is a new type of environmentally-friendly energy-saving technologies. Molten salts, one kind of phase-change materials, which have high latent heats, and whose phase transition temperatures match the high temperatures of heat engines, are the most widely used high-temperature phase-change heat storage materials. However, the heat transfer at solid/liquid phase interface belongs to Micro/Nanoscale Heat transfer, lots of the thermal properties of molten salt at melting point is difficult to test. In this investigation, based on the theory that the thermal conductivity can be determined by measuring the speed of the propagation of the solid/liquid phase interface during phase change, a set of system is developed to investigate the thermal conductivity of molten salts at liquid/solid phase transformation point. Meanwhile, mathematical calculation is applied to intuitively simulate the melting and solidifying process in the phase change chamber, by which the error could be analyzed and partly corrected and the result precision could also be increased. And a series of verification experiments have been performed to estimate the precision and the applicability of the measuring system to evaluate the feasibility of the method and measuring system. This research will pave the way to the follow-on research on heat storage at high temperature in industry.

scholarly journals Electrospun Shape-Stabilized Phase Change Materials Based on Photo-Crosslinked Polyethylene Oxide

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2979
Author(s):  
Giulia Fredi ◽  
Parnian Kianfar ◽  
Sara Dalle Vacche ◽  
Alessandro Pegoretti ◽  
Alessandra Vitale
Keyword(s):  
Thermal Properties ◽  
Phase Change ◽  
Polyethylene Oxide ◽  
Phase Change Materials ◽  
Fold Increase ◽  
Mechanical Tests ◽  
Molten State ◽  
Shape Stability ◽  
Human Thermal Comfort ◽  
Good Shape

Phase change materials (PCMs) in the form of fibers or fibrous mats with exceptional thermal energy storage ability and tunable working temperature are of high interest to produce smart thermoregulating textiles, useful for increasing human thermal comfort while avoiding energy waste. Common organic PCMs suffer from instability in their molten state, which limits their applicability as highly performing fibrous systems. In this work, electrospun fibrous mats made of polyethylene oxide (PEO), a PCM with excellent thermal properties and biocompatibility, were fabricated and their shape instability in the molten state was improved through UV photo-crosslinking. The characterization aimed to assess the performance of these shape-stable electrospun mats as nanofibrous PCMs for thermal management applications. In addition to an enhanced resistance to water-based solvents, UV-cured electrospun PEO mats demonstrated a remarkable latent heat (≈112 J/g), maintained over 80 heating/cooling cycles across the phase change temperature. Moreover, their morphological stability above their melting point was demonstrated both macroscopically and microscopically, with the retention of the initial nanofibrous morphology. Tensile mechanical tests demonstrated that the UV crosslinking considerably enhanced the ultimate properties of the fibrous mat, with a five-fold increase in both the tensile strength (from 0.15 MPa to 0.74 MPa) and the strain at break (from 2.5% to 12.2%) compared to the uncrosslinked mat. In conclusion, the photo-crosslinked electrospun PEO material exhibited high thermal properties and good shape stability without displaying leakage; accordingly, in the proposed PCM system, the necessity for encapsulation or use of a supporting layer has been eliminated. Photo-crosslinking thus proved itself as an effective, fast, and environmentally friendly method to dramatically improve the shape-stability of nanofibrous PEO electrospun mats for smart thermoregulating textiles.

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