**4. Conclusion**

LDPE/Cu composites prepared in solution was characterized by optic, spectroscopic and thermal analysis. The optical observation suggested that the copper powder particle distributions were found to be relatively uniform at both low and high copper contents. The presence of copper particles can improve the thermal stability of the composite since a maximum increment of 14°C is obtained comparing with the pure LDPE as shown on the TGA thermogram results. The results of DSC in standard conditions show that Cu content has little influence on the crystallinity Xc of LDPE. However, the trace of DSC at non-standard conditions suggested that the presence of copper microparticles has more effect on the network phase than that can be observed on the crystalline long range order phase. FTIR spectroscopy was used to study the phase content of LDPE in LDPE/Cu non-oriented composite films by investigate the CH2 rocking vibrations. Spectral simulation of the transmission spectra performed using a tow phase model show that the copper contents does not any effect in the phase composition of the LDPE matrix. According of three phases model the amount of the orthorhombic phase was found to be constant. However, the amorphous and the network phase fraction were found to respectively increase and decrease with the increase of copper particles load in the film. The presence of an inorganic filler (Cu) in an organic polymer matrix (LDPE) forms a hybrid material that merges the properties of the two families of materials that compose it. This type of LDPE/Cu composite material which exhibited good structural and thermal stability as a function of the Cu fraction can be used as a phase change material (PCM) by the addition of a suitable oil phase.
