4. Conclusions
Phase change materials based on high density polyethylene and
paraffin wax were thermal and mechanically characterized in this
work. The blends containing from 5 to 50 vol. % of wax were
extruded, and in spite of different melting temperatures of both
components no wax loss was detected after processing. This fact
was evaluated by means of thermogravimetric analyses. All the
prepared blends presented a pseudoplastic behaviour, being all of
them suitable to be injection moulded. DSC results showed a
displacement of melting temperature of polyethylene as a consequence
of the plasticization effect of wax. Glass transition temperature
of both components of blend was detected by dynamic
mechanical analysis revealing that there is not miscibility between
them. A decrease of Young’s modulus with wax content indicates
that the modulus of paraffin wax is lower than the modulus of
HDPE. As a consequence of this study, injection moulded blends of
HDPE and PW are highly suitable in phase change materials applications
owing to their lack of miscibility and their profitable
thermal and mechanical properties. The material is cheap, easy to
prepare, and posses a suitable latent heat and mechanical strength.