Thermal and Mechanical Properties of Expanded Graphite/Paraffin Gypsum-Based Composite Material Reinforced by Carbon Fiber

Abstract

Phase change material (PCM) is a kind of thermal energy storage material. Solid-liquid PCM composite materials must overcome the issues of material leakage and low thermal conductivity before they are suitable for widespread use in the fields of building and industry. In this study, porous expanded graphite (EG) is used as a carrier, which absorbs the PCM to fabricate EG/paraffin composites (EG/P) containing 90.6% paraffin, and a latent heat of up to 105.3 J/g was measured. Because gypsum board is widely used in buildings, therefore, EG/P composites are suitable to be integrated into gypsum to develop expanded graphite/paraffin gypsum-based composite material (EGPG) for thermal energy storage. In order to optimize the performance of EGPG, carbon fiber (CF) is used to reinforce their thermal and mechanical properties. The test results show that when 1 wt % CF is incorporated into the EGPG, the thermal conductivity increased 36.0%, and thus EGPG shows superior thermal control through the significantly increased efficiency of heat transfer. After 1 wt % CF was added, the flexural and compressive strength of EGPG were increased by 65.6% and 6.4%, respectively. The improved thermal and mechanical performance of EGPG modified by CF demonstrates that it is a structural-functional integrated building material suitable for building envelope system.

Synergistic Effect of Expanded Graphite-Silane Functionalized Silica as a Hybrid Additive in Improving the Thermal Conductivity of Cementitious Grouts with Controllable Water Uptake

“…In one of the works, Bao et al conducted infrared thermal image analysis to compare the performance of 20 wt% EGparaffin and 10 wt% graphene nanoplatelets (GNPs)-paraffin, which were used as the composite phase change materials in the developed cement-based composites, resulting in a better thermal regulatory performance with GNP due to its high thermal conductivity coefficient [15]. Furthermore, Zhang et al fabricated EG/paraffin gypsum-based composite with 1 wt% carbon fiber and increased the thermal conductivity by 36.0% and 28.6% with the addition of 10% and 20% EG, respectively [16]. Accordingly, the recent investigations clearly show the potential of EG for use as a phase change material and its direct use in grout mixes without any required surface modification, especially in paraffin systems.…”

Preparation and Characterization of Paraffin/Mesoporous Silica Shape-Stabilized Phase Change Materials for Building Thermal Insulation

“…[ 12 , 13 , 14 ]. In particular, shape-stabilized phase change materials (SS-PCMs) consisting of one or several types of PCMs and a supporting porous matrix, such as graphite [ 15 ], carbon foam [ 16 ], or carbon nanotubes [ 17 ], are generally preferred. The investigations on PCMs mainly focus on the improvement of thermal conductivity [ 18 ].…”

Role of Phase Change Materials Containing Carbonized Rice husks on the Roof-Surface and Indoor Temperatures for Cool Roof System Application

“…Carbonized materials are widely used to improve the thermal conductivity, which results in the prevention of supercooling and phase segregation. Additionally, they possess favorable properties such as noncorrosion by contact with PCMs, chemical stability, nontoxicity, and being lightweight [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Amongst the carbon materials with these advantages, carbonized rice husks (CRHs) are inexpensive as they are waste materials that can be easily obtained.…”