Shape Stability of Polyethylene Glycol/Acetylene Black Phase Change Composites for Latent Heat Storage

Jingjing Zhang,Ruonan Shi,Zhiping Luo,Ming Jiang,Hairong Li,Chuanxi Xiong,Junyang Tu

doi:10.1155/2018/3954163

Abstract

Sufficient shape stability is essential for a high-performance phase change material (PCM). Although significant advances have been made to develop form-stable composites, technical development in the field of polymer-based PCMs is currently limited by an incomplete understanding of the shape stability. Form-stable polyethylene glycol/acetylene black (PEG/AB) PCMs containing PEGs with different average molecular weights have been obtained by melt mixing to investigate the shape stability of the PEG/AB composites. It was found that the phase change behaviors of the PEG/AB composites were not only attributed to the interactions between the AB and PEG, but also to the intermolecular interactions of the PEG chains, depending on the varying molecular weights of the PEGs. Physically crosslinked structure with temporary junctions was formed through hydrogen bonding, capillary, surface tension forces, intermolecular friction, and macromolecular entanglement, which contributed to the constrained chain motion and thus the solid-solid phase change behavior of the PEG/AB composites. The physically crosslinked structure was more stable with longer length of the PEG molecular chains, resulting in higher critical impregnated contents of the PEG into the AB and thus improved latent heat.

Highlights

Energy storage can optimize the energy flows to overcome the mismatch between the demand for energy and the supply of energy, especially for energy generated by variable and renewable resources, such as water, wind, and solar energy [1]
Significant advances have been made, technical development in the field of polymer-based phase change material (PCM) is currently limited by an incomplete understanding of the shape stability. e affinity of support fillers to PCMs depends on their structures, so the structure of the fillers usually is a primary consideration for the shape stability
E C-O stretching vibration was at 1106 cm−1. e Fourier-transform infrared (FTIR) results indicate that no significant new peaks were observed other than characteristic peaks of polyethylene glycol (PEG) and acetylene black (AB) at FTIR spectrums of the polyethylene glycol/acetylene black (PEG/AB) composites (Figure 1(b)), which proves that the interactions between the functional groups of PEG and AB are physical in nature

Summary

Introduction

Energy storage can optimize the energy flows to overcome the mismatch between the demand for energy and the supply of energy, especially for energy generated by variable and renewable resources, such as water, wind, and solar energy [1]. E latent heat capacities of the composite PCMs containing the PEGs with di erent Mw are obviously lower than those of the pristine PEGs due to the incorporation of the AB that does not undergo phase change.

Results

Conclusion