Abstract In this work, a Shape-stabilized phase change materials were prepared by absorbing hexadecane into the network of styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) tri-block copolymer and coating them with a low-density polyethylene (LDPE). The four composites were prepared at different mass fractions of Hexadecane/SEBS (80/5, 75/10, 65/20, 55/30, w/w %) with 15% of LDPE by the melt-mixing method. Thermal conductivities and diffusivities were evaluated using a Hot Disk Thermal Constants Analyzer (TPS 2500S) and the Transient Guarded Hot Plate Technique (TGHPT) was used to investigate thermal storage and release capacity of the composites. Results were compared to DSC/TGA data. The thermal properties of the composite were improved by the incorporation of the Hexadecane, where the latent heat of composites increased from 106.15 kJ/kg to 179.76 kJ/kg for the composite containing 80% PCM. Interestingly, the mass fraction of Hexadecane could reach approximately 80% with a good form stability, which surmounts almost all mass fraction values reported in the literature.