Funktionalisierung polymerer Phasenwechselmaterialien

Translated title of the contribution: Functionalization of Polymeric Phase Change Materials

Bettina Strommer

Research output: ThesisMaster's Thesis


This study dealt with the development of polymeric phase change materials (PCM) with two storage temperatures and their characterization as to application-relevant thermo-physical properties. Thus, on the one hand polypropylene (PP) and high density polyethylene (HDPE, two grades) were blended with paraffin wax (70:30 and 50:50 wt.%), respectively. On the other hand one HDPE grade was blended with either polyethylene glycol (PEG), linear low density polyethylene (LLDPE) and polyamide 6 (PA6; 50-50 wt.%). The blending types included compounding (dispersion via twin screw extruder), statistic mixture (manual blending of granules) and layer mixture (layers of granules). The materials (100 g to 200 g) were exposed statically in air in the melted state (exposure temperature min. 20 °C above the melting temperature of the higher melting component) for up to 1440 h in glass jars. After different exposure times the specimen were characterized as to mixing behavior, thermo-oxidative stability and storage capacity. The main focus was on evaluating their applicability as PCM. The investigated PP-paraffin blends exhibited an insufficient thermo-oxidative stability. In general PP is not applicable as PCM. However, HDPE-paraffin and HDPE-polymer blends are applicable as PCM. The storage capacity of these materials remained constant over the investigated exposure times. During the exposure a thermo-oxidative degraded surface layer was formed, which sealed the specimen and protected it from – if already occurred, further - degradation inside the bulk . For the HDPE-paraffin blends (storage capacity of 100-102 J/g for 50:50 w.%, 61 J/g for 70:30 w.% at 86 °C and 110 J/g for 50:50 w.%, 153 J/g for 70:30 w.% at 136 °C – however the melting peaks overlap partly), which generally did not show any phase separation, the blending type affected the protective surface layer’s formation time: for the compound the surface layer already occurred within an exposure time of 160 h; for the statistic mixtures, the protective surface layer occured after an exposure time of 300 h. This effect correlated with the zero shear viscosity of the materials. The HDPE-LLDPE blends showed partially phase segregation during the exposure to static thermal load. This polymeric PCM exhibited a large storage temperature range with two melting peaks, whereas the dominating peak depends on the local material composition. The storage capacity ranged between136-154 J/g at 128 °C and between 155-184 J/g at 133 °C. For the HDPE-PEG blends (storage capacities of 78 J/g at 66 °C and 110 J/g at 135 °C) and HDPE-PA6 blends (storage capacities of 107 J/g at 135 °C and 33 J/g at 220 °C) the exposure to static thermal load yielded a distinct phase separation, wheras the polymer with the lower density formed the upper layer. The high exposure temperature applied for the HDPE-PA6 blends caused an initial reduction of the storage capacities of both materials in the bulk (9% for HDPE; 6% for PA6 after an exposure time of 240 h). However, the storage capacities did not alter further with increasing exposure time.
Translated title of the contributionFunctionalization of Polymeric Phase Change Materials
Original languageGerman
Awarding Institution
  • Montanuniversität
  • Resch-Fauster, Katharina, Supervisor (internal)
Award date20 Dec 2019
Publication statusPublished - 2019

Bibliographical note

no embargo


  • Latent Heat Storage
  • Phase Change Material
  • PCM
  • Polymerblend
  • Polyethylene
  • HDPE
  • Polypropylene
  • PP
  • Paraffin
  • Paraffin Wax
  • Polyethyleneglycol
  • PEG
  • Polyamide
  • PA6

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