An Enhancement of Compositional Stability of Phase Change Materials by Lamination with Aluminum Sheet

Abstract

The wax leakage from shape-stabilized phase change materials (SSPCMs) is a limitation because it reduces their functionality. In this work, an enhancement of the compositional stability of SSPCMs formed by high-density polyethylene (HDPE) and paraffin wax blends through a lamination by aluminum (Al) foil was studied. The materials' thermal conductivity was enhanced by adding expanded graphite (EG). The lamination of SSPCMs is the simplest method of reducing leakage, but it suffers from poor adhesion between polymer-based blends and protecting layers. The improved adhesion between SSPCMs and Al foil was achieved by adding 2 wt.% of maleated polyethylene (PE) acting as an adhesion promoter into SSPCMs or by plasma treatment of both SSPCMs and Al surfaces. Microscopic, spectroscopic, and optical techniques were used to analyze the surface and adhesion properties of SSPCMs. The peel resistance of SSPCMs after plasma treatment or modification by maleated PE increased from 2.2 N/m to 7.2 N/m or 55.1 N/m, respectively. The wax leakage from the treated or modified SSPCMs was suppressed significantly. The plasma-treated or maleated PE-modified SSPCMs showed leakage of 0.5 wt.% or 0.2 wt.%, respectively, after three days of leakage test. It indicates a good potential of this treatment/modification for industrially applied SSPCMs.