The observed clear weight loss is due to paraffin evaporation. And, the earlier occurrence of rapid weight loss of paraffin/DP composite PCM may be attributed to physical behavior difference between free paraffin and pore-confined paraffin.
Moreover, no decomposition is observed for paraffin/DP composite PCM within 150 C, showing good thermal stability of this fabricated composite PCM.
Also, as shown in Fig. 7, the total weight loss of paraffin/DP composite PCM measured in TGA test is 47.1%, which is quite close to the design 47.4%. It proves the homogenous preparation of paraffin/DP mixture.