Investigation of thermally conducting phase‐change materials based on polyethylene/wax blends filled with copper particles

Abstract

This article reports on the morphology, melting and crystallization behavior, thermal stability, tensile properties, and thermal conductivity of phasechange materials (PCM) for thermal energy storage. These materials were based on a soft Fischer-Tropsch paraffin wax (PCM) blended with low-density polyethylene, linear low-density polyethylene, and high-density polyethylene. These immiscible blends were melt-mixed with copper (Cu) microparticles (up to 15 vol %) to improve the thermal conductivity in the matrix material. The presence of the Cu microparticles in the PCMs did not significantly change the crystallization behavior, thermal stability, or tensile properties of the blend composites in comparison with the corresponding polyethylene/wax blends and polyethylene/Cu composites. The observed differences were related to the fact that the wax seemed to have a higher affinity for the Cu particles than any of the polyethylenes, and so it crystallized as a layer around the Cu particles. The thermal conductivity of the samples increased almost linearly with increasing Cu content, but the samples had slightly lower values than the corresponding polyethylene/Cu composites, probably because of the lower thermal conductivity of the wax.

Thermally conductive phase-change materials for energy storage based on low-density polyethylene, soft Fischer–Tropsch wax and graphite

“…Some of them [9,10] There are very few reports on the improvement of the thermal conductivity of polyethylene/PCM blend materials. Molefi et al [15][16][17] investigated the morphology, thermal and thermomechanical properties, as well as the thermal conductivities, of different polyethylenes mixed with different amounts of Fischer-Tropsch paraffin wax, as well as different amounts of copper micro-and nanoparticles. They found that the presence of the wax had the biggest influence on the mechanical properties of the phase-change composites, and that the wax preferably crystallized around the copper particles.…”

Influence of the presence of medium-soft paraffin wax on the morphology and properties of iPP/silver nanocomposites

“…An increase in the thermal conductivity of the composites with increasing filler content was observed, as well as the formation of thermally conductive paths. However, one of the papers [12] reported an initial decrease in thermal conductivity at low filler contents, which increased at higher filler loadings. This was attributed to the voids that formed at the interface between the polymer and the wax.…”

“…However, the presence of wood filler particles in the polymer/wax blends reduced the storage modulus [11]. The thermal conductivity of form-stable PCM composites was investigated in a number of studies [5,[12][13][14][15]. An increase in the thermal conductivity of the composites with increasing filler content was observed, as well as the formation of thermally conductive paths.…”

The influence of metal nanoparticles on the mechanical properties of composite materials

“…Наночастицы меди распределяют в таких полимерах, как поливи-нилхлорид [38], полиэтилен [39,40], полипропилен [12,41,42], поли-стирол [43][44][45]. Важным требованием при синтезе таких композитных материалов является приобретение специфических свойств меди без утраты уже имеющихся свойств полимера (особенно прочностных па-раметров).…”

“…Воск, внедренный в полимерную матрицу полиэтилена, применя-ется для хранения тепла солнечной энергии; тепловой защиты элек-тронных устройств, пищевых продуктов и изделий медицинского на-значения; снижения установленной мощности и теплового комфорта в транспортных средствах [40]. Такие характеристики материала до-стигаются за счет плавления и кристаллизации воска, в процессе кото-рых происходит накопление или высвобождение большого количества энергии.…”