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AuthorSobolčiak, Patrik
AuthorMrlik, Miroslav
AuthorPopelka, Anton
AuthorMinařík, Antonín
AuthorIlcikova, Marketa
AuthorSrnec, Peter
AuthorNogellova, Zuzana
AuthorOuederni, Mabrouk
AuthorKrupa, Igor
Available date2023-06-26T04:54:19Z
Publication Date2021
Publication NamePolymers
ResourceScopus
URIhttp://dx.doi.org/10.3390/polym13121987
URIhttp://hdl.handle.net/10576/44825
AbstractFoamed 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.
SponsorThis work was made possible by NPRP grant No.: 13S-0127-200177 from the Qatar National Research Fund (A Member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors. M.M. and M.I. gratefully acknowledges the Ministry of Education, Youth and Sports of the Czech Republic—DKRVO (RP/CPS/2020/003).
Languageen
PublisherMDPI
SubjectDynamic mechanical analysis
Foams
Micro-computed tomography
Paraffin wax
Phase change materials
Recycled polyethylene
TitleFoamed phase change materials based on recycled polyethylene/paraffin wax blends
TypeArticle
Issue Number12
Volume Number13
dc.accessType Open Access


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