scholarly journals Foamed Phase Change Materials Based on Recycled Polyethylene/Paraffin Wax Blends

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1987
Author(s):  
Patrik Sobolčiak ◽  
Miroslav Mrlik ◽  
Anton Popelka ◽  
Antonín Minařík ◽  
Marketa Ilcikova ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Mechanical Stability ◽  
Organic Peroxide ◽  
Mechanical Analysis ◽  
Paraffin Wax ◽  
Micro Computed Tomography ◽  
Scanning Calorimetry ◽  
The Real

Foamed phase-change materials (FPCMs) were prepared using recycled linear low-density polyethylene (LLDPE) blended with 30 wt.% of paraffin wax (PW) and foamed by 1,1′-azobiscarbamide. The protection of pores’ collapse during foaming process was insured through chemical cross-linking by organic peroxide prior foaming. This work represents one of very few attempts for a preparation of polymeric phase change foams without a use of micro-encapsulated phase change component leading to the enhancement of the real PCM component (PW) within a final product. The porous structure of fabricated foams was analyzed using micro-computed tomography, and direct observation, and reconstruction of the internal structure was investigated. The porosity of FPCMs was about 85–87 vol.% and resulting thermal conductivity 0.054–0.086 W/m·K. Differential Scanning Calorimetry was used to determine the specific enthalpies of melting (22.4–25.1 J/g) what is the latent heat of materials utilized during a heat absorption. A stability of samples during 10 heating/cooling cycles was demonstrated. The phase change changes were also investigated using the dynamic mechanical analysis from 0° to 65 °C during the 10 cycles, and the mechanical stability of the system and phase-change transition were clearly confirmed, as proved by DSC. Leaching test revealed a long-term release of PW (around 7% of its original content) from samples which were long term stored at temperatures over PW melting point. This is the usual problem concerning polymer/wax blends. The most common, industrially feasible solution is a lamination of products, for instance by aluminum foils. Finally, the measurement of the heat flow simulating the real conditions shows that samples containing PW decrease the energy passing through the sample from 68.56 to 34.88 kJ·m−2. In this respect, FPCMs provide very effective double functionality, firstly common thermal insulators, and second, as the heat absorbers acting through melting of the PW and absorbing the excessive thermal energy during melting. This improves the heat protection of buildings and reduces temperature fluctuations within indoor spaces.

Long-term thermophysical behavior of paraffin wax and paraffin wax/polyaniline (PANI) composite phase change materials

2020 ◽  
Vol 31 ◽  
pp. 101568
Author(s):  
Mathew George ◽  
A.K. Pandey ◽  
Nasrudin Abd Rahim ◽  
V.V. Tyagi ◽  
Syed Shahabuddin ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Paraffin Wax ◽  
Pani Composite ◽  
Composite Phase Change Materials

scholarly journals A Novel Polymeric Adsorbent Embedded with Phase Change Materials (PCMs) Microcapsules: Synthesis and Application

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 736 ◽  
Author(s):  
Xingang Li ◽  
Lingyu Sun ◽  
Hong Sui ◽  
Lin He ◽  
Wei Yuan ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Gas Adsorption ◽  
High Specific Surface Area ◽  
Paraffin Wax ◽  
Heat Of Fusion ◽  
Scanning Calorimetry ◽  
Polymeric Adsorbent ◽  
Adsorption Column ◽  
Dominant Structure

The heat released during the industrial gas adsorption (e.g., volatile organic compounds (VOCs)) on adsorbents (e.g., activated carbon) would lead to the risks of fire and explosion in the adsorption column. Herein, a novel highly-porous Vinylbenzyl chloride-Divinylbenzene (VBC-DVB) polymeric adsorbent was synthesized with embedded microcapsules (Hypercrosslinked VBC-DVB Beads (HVPM)). These microcapsules have a polydivinylbenzene-phase change materials (DVB-PCMs) core-shell structure. Paraffin wax was used as PCM filling in the spherical capsule. This microcapsules-embedded polymeric adsorbent HVPM (Φ1.5–2.0 mm) is found to possess a high specific surface area (~665 m²/g) and micropore-dominant structure. It also has heat storage capability indicated by DSC (Differential Scanning Calorimetry) analysis (11.1 J/g heat of fusion between 35.0 and 48.2 °C) for the encapsulated paraffin wax. The lab adsorption tests proved the capabilities of HVPM in adsorbing VOCs (toluene, 0.21 g/g) and controlling the temperature inside the adsorption column during the dynamic adsorption process, in which the temperature rise was lowered by 62.5%, relatively.

Enhancement of Separated Ultra Pure n-paraffin as Phase Change Materials (PCM) by W-Fe Bimetallic Oxides

2020 ◽  
Vol 10 (6) ◽  
pp. 817-826
Author(s):  
Fathi S. Soliman ◽  
Heba H. El-Maghrabi ◽  
Tamer Zaki ◽  
Amr A. Nada ◽  
Fouad Zahran
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Optical Microscope ◽  
Paraffin Wax ◽  
Scanning Calorimetry ◽  
Latent Heat Storage ◽  
Paraffin Waxes ◽  
Bimetallic Oxides

Objective:: Six ultra pure Paraffin Waxes (PW) were successfully fractionated at 35°, 30°, 25°, 20°, 15° and 10°C. The bimetallic oxide (Ferberite) was successfully synthesized by Microwave assisted method. Methods: Enhanced Phase Change Materials (PCMs) were designed by loading W/Fe bimetallic oxides in the ultra pure PW matrix at 1, 2, 3, 4 and 5 wt. %. paraffin wax, W/Fe bimetallic oxide and the resultant composite blends were characterized by X-ray Diffraction (XRD), Gas Chromatography (GC), Deferential Scanning Calorimetry (DSC), Polarized Optical Microscope (POM), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). In addition to testing the thermal conductivity of the designed blends. According to SEM, DSC and POM data, the prepared nanocomposite was homogeneously dispersed into the selected PW matrix. Results: Data revealed that thermal conductivity of the designed composite increases with increasing the loading ratio of W-Fe bimetallic oxides. The total latent heat storage ΔHT of the initial sample was improved from 295.91 J/g to 311.48 J/g at 5 wt. % loading percent. Conclusion:: Thermal conductivity was improved from 8.54 to 21.77 W/m2k with increasing up to 255% in comparison with pure paraffin wax.

Polyamide as a Matrix for the Creation of Form-Stable Phase Change Materials

2009 ◽  
Vol 610-613 ◽  
pp. 414-418 ◽  
Author(s):  
Jing Guo ◽  
Nan Li
Keyword(s):  
Block Copolymer ◽  
Phase Change ◽  
Phase Change Materials ◽  
Polyamide 6 ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
Thermal Reliability ◽  
Scanning Calorimetry ◽  
X Ray

Phase change materials (PCMs) with storing and releasing energy properties have been widely used in lots of fields such as solar energy storing, smart housing, thermo-regulated fibers, and agricultural greenhouse. Here, PCMs based on polyamide 6 (PA6) blended with Polyethylene glycol (PEG) was studied. In order to improve the compatibility between PA6 and PEG, a PA6-PEG block copolymer was synthesized and added to the blends. The structure and properties of the block copolymer were determined by Fourier Transform Infrared (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and optics microscope (OM). The results of DSC analysis showed that tThe copolymer block is phase separated. DSC results also showed that the phase transition temperature of the blend is different from that of pure PEG, indicating the interaction occurrence between PEG and PA6 by using PA6-PEG block copolymer, the latent heat of PEG/PA6 blend increased with the mass percent of PEG. The results of tThermal cycling tests showed that the blend as a PCM has good long-term thermal reliability.

Accelerated long-term assessment of thermal and chemical stability of bio-based phase change materials

2016 ◽  
Vol 40 (4) ◽  
pp. 299-310 ◽  
Author(s):  
Jignesh S Patel ◽  
Elizabeth Gao ◽  
Veera M Boddu ◽  
Larry D Stephenson ◽  
Ashok Kumar
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Chemical Stability ◽  
Phase Change Materials ◽  
Scanning Calorimetry ◽  
Change Material ◽  
Scanning Electron

Thermal energy storage systems incorporated with phase change materials have potential applications to control energy use by building envelopes. However, it is essential to evaluate long-term performance of the phase change materials and cost-effectiveness prior to full-scale implementation. For this reason, we have used the accelerated long-term approach for studying the thermal performance and chemical stability of a commercially available bio-based phase change material during thermal cycling over a simulated period of 20 years. The phase change material was subjected to accelerate thermal aging under controlled environmental conditions. Small samples of the phase change material were periodically removed to measure its latent heat, thermal decomposition, and chemical stability using various analytical methods such as differential scanning calorimetry, thermogravimetry analysis, and infrared spectroscopy. The topographic changes in the phase change material due to the aging process were observed using scanning electron microscopy. The differential scanning calorimetry data indicate a significant reduction of 12% in the latent heat during heating and cooling cycles during the initial 6.2 years remain nearly constant thereafter. The thermogravimetry analysis results showed that the phase change material has excellent thermal stability within the working temperature range and also shows long-term decomposition temperature stability. The Fourier transform infrared spectra of the phase change material indicate absorption of moisture but the phase change material was chemically stable over the duration of accelerated aging cycles. After several aging cycles, the baseline surface morphology appeared to be changed from uniform mix of phase change material with microstructures to segregated microstructures as evidenced by the observation of the scanning electron micrographs.

scholarly journals pH-controlled synthesis of sustainable lauric acid/SiO2 phase change material for scalable thermal energy storage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shafiq Ishak ◽  
Soumen Mandal ◽  
Han-Seung Lee ◽  
Jitendra Kumar Singh
Keyword(s):  
Electron Microscopy ◽  
Phase Change ◽  
Lauric Acid ◽  
Photoelectron Spectroscopy ◽  
Phase Change Materials ◽  
Precursor Solution ◽  
Thermal Reliability ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Heating And Cooling

AbstractLauric acid (LA) has been recommended as economic, eco-friendly, and commercially viable materials to be used as phase change materials (PCMs). Nevertheless, there is lack of optimized parameters to produce microencapsulated PCMs with good performance. In this study, different amounts of LA have been chosen as core materials while tetraethyl orthosilicate (TEOS) as the precursor solution to form silicon dioxide (SiO2) shell. The pH of precursor solution was kept at 2.5 for all composition of microencapsulated LA. The synthesized microencapsulated LA/SiO2 has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The SEM and TEM confirm the microencapsulation of LA with SiO2. Thermogravimetric analysis (TGA) revealed better thermal stability of microencapsulated LA/SiO2 compared to pure LA. PCM with 50% LA i.e. LAPC-6 exhibited the highest encapsulation efficiency (96.50%) and encapsulation ratio (96.15%) through Differential scanning calorimetry (DSC) as well as good thermal reliability even after 30th cycle of heating and cooling process.

scholarly journals Characterization of Unripe and Mature Avocado Seed Oil in Different Proportions as Phase Change Materials and Simulation of Their Cooling Storage

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 107
Author(s):  
Evelyn Reyes-Cueva ◽  
Juan Francisco Nicolalde ◽  
Javier Martínez-Gómez
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Seed Oil ◽  
Energy System ◽  
Maturity Stage ◽  
Natural Environments ◽  
Renewable Materials ◽  
Scanning Calorimetry ◽  
Avocado Seed

Environmental problems have been associated with energy consumption and waste management. A solution is the development of renewable materials such as organic phase change materials. Characterization of new materials allows knowing their applications and simulations provide an idea of how they can developed. Consequently, this research is focused on the thermal and chemical characterization of five different avocado seed oils depending on the maturity stage of the seed: 100% unripe, 25% mature-75% unripe, 50% mature-50% unripe, 75% mature-25% unripe, and 100% mature. The characterization was performed by differential scanning calorimetry, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The best oil for natural environments corresponded to 100% matured seed with an enthalpy of fusion of 52.93 J·g−1, and a degradation temperature between 241–545 °C. In addition, the FTIR analysis shows that unripe seed oil seems to contain more lipids than a mature one. Furthermore, a simulation with an isothermal box was conducted with the characterized oil with an initial temperature of −14 °C for the isothermal box, −27 °C for the PCM box, and an ambient temperature of 25 °C. The results show that without the PCM the temperature can reach −8 °C and with it is −12 °C after 7 h, proving its application as a cold thermal energy system.

Methods for Separation of Copper Oxide Nanoparticles From Colloidal Suspension in Dodecane

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohammed H. Sheikh ◽  
Muhammad A. R. Sharif
Keyword(s):  
Energy Storage ◽  
Copper Oxide ◽  
Phase Change ◽  
Phase Change Materials ◽  
Research Work ◽  
Cuo Nanoparticles ◽  
Health Hazards ◽  
Suspension Stability ◽  
Reduced Pressure

Phase change materials (PCM) are used in many energy storage applications. Energy is stored (latent heat of fusion) by melting the PCM and is released during resolidification. Dispersing highly conductive nanoparticles into the PCM enhances the effective thermal conductivity of the PCM, which in turn significantly improves the energy storage capability of the PCM. The resulting colloidal mixture with the nanoparticles in suspension is referred to as nanostructure enhanced phase change materials (NEPCM). A commonly used PCM for energy storage application is the family of paraffin (CnH2n+2). Mixing copper oxide (CuO) nanoparticles in the paraffin produces an effective and highly efficient NEPCM for energy storage. However, after long term application cycles, the efficiency of the NEPCM may deteriorate and it may need replacement with fresh supply. Disposal of the used NEPCM containing the nanoparticles is a matter of concern. Used NEPCM containing nanoparticles cannot be discarded directly into the environment because of various short term health hazards for humans and all living beings and unidentified long term environmental and health hazards due to nanoparticles. This problem will be considerable when widespread use of NEPCM will be practiced. It is thus important to develop technologies to separate the nanoparticles before the disposal of the NEPCM. The primary objective of this research work is to develop methods for the separation and reclamation of the nanoparticles from the NEPCM before its disposal. The goal is to find, design, test, and evaluate separation methods which are simple, safe, and economical. The specific NEPCM considered in this study is a colloidal mixture of dodecane (C12H26) and CuO nanoparticles (1–5% mass fraction and 5–15 nm size distribution). The nanoparticles are coated with a surfactant or stabilizing ligands for suspension stability in the mixture for a long period of time. Various methods for separating the nanoparticles from the NEPCM are explored. The identified methods include: (i) distillation under atmospheric and reduced pressure, (ii) mixing with alcohol mixture solvent, and (iii) high speed centrifugation. These different nanoparticle separation methods have been pursued and tested, and the results are analyzed and presented in this article.

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