Fabricated Polyethylene glycol/ hydroxylated carbon nanotubes shape-stabilized phase change materials with improving thermal conductivity

Abstract

To improve the thermal conductivity and shape-stability of polyethylene glycol (PEG), a series of novel PEG based phase change materials (PPCs) have been successfully synthesized by grafted polymerization, in which PEG as the phase change ingredient, hydroxylated carbon nanotubes (HCNTs) as the thermal conductive filler and γ-glycidyl ether oxypropyl trimethoxysilane (KH-560) as the bridge. The results indicate that the HCNTs does not agglomerate during phase transition since the HCNTs are introduced into the molecular structure of the PEG by KH-560. So, it can maintain good thermal conductivity and thermal stability after 100 thermal cycles. As the result, the latent heat of phase change for PPC is in the range of 119.9 ∼ 127.9 J·g−1, and the phase transformation temperature is in the field of 311.7 ∼ 330.9 K. The thermal conductivity of the PPC is 0.7081 W·m−1·K−1 as adding 9.0 wt% HCNTs, which is 2.2 times that of pure PEG. The temperature regulation experimental results reveal that PPC5 has an obvious buffering effect in the temperature ranges of 311.7 ∼ 330.9 K during the heating and cooling process. It shows good potential for application in thermal energy storage and temperature regulation.