scholarly journals Form-Stable Phase Change Materials Based on SEBS and Paraffin: Influence of Molecular Parameters of Styrene-b-(Ethylene-co-Butylene)-b-Styrene on Shape Stability and Retention Behavior

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3285
Author(s):  
Ralf Rickert ◽  
Roland Klein ◽  
Frank Schönberger

In this work, the influence of molecular parameters of styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) triblock copolymer as matrix material in form-stable phase change material (FSPCM) on the thermo-mechanical properties and leakage behavior are studied. Various SEBS grades differing in their molecular weight, styrene content, and ethylene/butylene ratio are used as supporting matrix in composites with 90 wt.% paraffin. Thermo-mechanical properties are determined by rheological measurements. The results show phase transitions temperatures from solid to hard gel, hard gel to soft gel, and soft gel to gel fluid. Paraffin leakage in FSPCM is analyzed by mass loss over time in an oven at 60 °C. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are applied to determine the thermal energy storage capacity. Finally, the molecular weight and the styrene content are combined to the molecular weight of styrene block which is identified as the authoritative parameter for the thermo-mechanical properties of the SEBS/PCM composite.

2011 ◽  
Vol 239-242 ◽  
pp. 1101-1104
Author(s):  
Jing Guo ◽  
Heng Xue Xiang ◽  
Cheng Nv Hu

Using stearic acid-lauric acid binary of fatty acid as phase change material, waste polyacrylonitrile fiber (PAN) as supporting material, organic montmorillonite (OMMT) as modifier, and N, N-dimethylformamide as solvent, OMMT-PAN-binary fatty acid composite phase change materials(PCM) is prepared by solution blending. Using Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Thermogravimetric analysis (TG) study the structure and properties of PCM, the optimized preparation techniques of PCM obtained by orthogonal tests. SEM results showed that the PCM was homogeneous structure, binary of fatty acid dispersed in the continuous phase PAN; TGA results indicated that the degradation of the phase change material can be divided into three steps; DSC results showed that the crystallization enthalpy of PCM reached 143.27 J/g, the phase change temperature was around 23°C, and the DSC thermal circulation showed good thermal stability of the PCM; cooling curve showed that the PCM had good heat insulation properties, holding time reached 800s, and after repeated thermal circulation, heat insulation properties remained the same.


2021 ◽  
Vol 20 (3) ◽  
pp. 135-144
Author(s):  
Tomasz Bien

The paper describes the research on the method of production of granulated phase-change materials (PCM) used in construction industry for the accumulation of thermal energy. As mineral materials for the granules preparation zeolite from fly ash Na-P1 and natural diatomite dust were used which were impregnated with paraffinic filtration waste and granulated using a combined granulation method. Obtained granules were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherm, and differential scanning calorimetry (DSC). Mechanical strength of the materials was determined in a “drop strength” test. Performed analyses revealed that mineral composition and micromorphology of the diatomite and zeolite granules were varied, with zeolite granules having higher mechanical strength.


2014 ◽  
Vol 703 ◽  
pp. 3-8 ◽  
Author(s):  
Jing Guo ◽  
Xiang Kang You ◽  
Li Zhang ◽  
Heng Xue Xiang ◽  
Sen Zhang ◽  
...  

In this study, novel solid–solid phase change materials (PCM) composed of polyacrylonitrile, binary of fatty acids ((blending of stearic acid (SA) and lauric acid (LA)) and zeolite molecular sieve (ZMS) were prepared by solution blending process. The structure and properties of the PCM were characterized using flourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), polarized optical microscopy (POM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TG), respectively. DSC analysis indicated that the crystallization latent heat of the PCM was 125.22 J/g and its phase transition temperature was about 17 °C. The temperature curve for step cooling of the PCM showed that it’s holding time achieved 1 480 s, which explains that the PCM had excellent heat-insulating properties. Based on all results it can be concluded that the novel PCM can be considered as potential PCM for thermal energy storage.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Junwei Zhang ◽  
Yan Chen ◽  
Zeguang Nie ◽  
Zhengshou Chen ◽  
Junkai Gao

AbstractIn this study, silver microspheres (SMS) were introduced into cotton stalk porous-carbon (CSP) to prepare silver microsphere doping porous-carbon (SMS-CSP), and then SMS-CSP was used as the matrix of polyethylene glycol (PEG) to synthesize shape-stable phase change material of PEG/SMS-CSP. It was found that the introduction of SMS into CSP could not only greatly improve the loading capacity of the porous-carbon for PEG, but also could increase the thermal conductivity of PEG/SMS-CSP. Additionally, the method of introducing SMS into porous-carbon had the advantages of environmental protection and simple operation. Moreover, the raw material of cotton stalk is a kind of agricultural waste, which has the merits of wide source, low price and easy to obtain. Furthermore, in the preparation of cotton stalk porous-carbon, with the increase of pyrolysis temperature the thermal conductivity of PEG/SMS-CSP could be enhanced significantly. The mechanism about the enhancement of thermal conductivity was clarified, which could provide more basic theory for the study about the thermal conductivity of shape-stable phase change materials (ss-PCMs) based on porous-carbon.


Author(s):  
Navin Kumar ◽  
Debjyoti Banerjee

“T-history method” is widely used for characterization of thermal properties of Phase Change Material (PCM). In this study improvements are proposed to the experimental protocol used in the conventional T-History method. Experimental validation of numerical predictions for various samples of PCM were performed using the proposed measurement technique. This enabled the evaluation of the improvements in the proposed approach as well as for analyzing the experimental results. This involved measurement of temperature at the surface and in the center of the PCM samples (as well as that of the reference sample materials). The proposed modifications enable enhanced accuracy for estimation of the material properties (when compared to the conventional approaches). The estimates from the proposed approach were observed to be within 10% of the measured values obtained using Differential Scanning Calorimetry (DSC). The proposed approach is amenable to testing large sample sizes, is simpler to implement, provides more rapid data collection and is more cost-effective than that obtained using standard DSC protocols.


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