Preparation And Properties Of Graphene Reinforced Phase Change Cement-based Materials

Building energy consumption plays a decisive role in total energy consumption in China,With the rapid development of society,building energy conservation has received more and more attention.Actively improving energy efficiency in buildings can effectively alleviate the problem of energy shortage in China.The phase change material absorbs or releases energy during the phase change process,so it can be applied to the building by utilizing the latent heat storage function of the phase change material to realize the temperature regulation function of the room and improve the energy utilization rate.In this paper,four kinds of organic phase change materials（PCMs）of paraffin,stearic acid,butyl stearate and lauric acid were used,and attapulgite as the adsorption material was prepared.The attapulgite composite shape-stabilized phase change material was prepared by vacuum adsorption method.The diffusion exudation ring found that the lauric acid was the best phase change materials with attapulgite,and the optimal ratio was 1:1.5.In order to improve the thermal conductivity of the phase change material,lauric acid organic phase change material was prepared by dispersing graphene into lauric acid by ultrasonic dispersion method.The lauric acid organic phase change material was used as the phase change material,and the attapulgite was used as the adsorption material.The lauric acid/attapulgite composite shape-stabilized phase change material was prepared by vacuum adsorption method.Then prepared attapulgite composite shape-stabilized phase change material and lauric acid/attapulgite composite shape-stabilized phase change material were mixed into cement-based materials to study the effects on the mechanical properties and thermophysical properties of cement-based materials.Finally,graphene reinforced phase change energy storage cement-based materials were prepared and the effects on the properties of cement-based materials were studied.The lauric acid/attapulgite composite shape-stabilized phase change material were characterized using diffusion-permeation method,FT-IR,SEM and DSC.The diffusion exudation ring found that the optimum adsorption amount was 1:1.4.FT-IR found that only the physical adsorption between lauric acid and attapulgite.SEM found that attapulgite can adsorb phase change materials very well.DSC found that the phase transition temperature of the auric acid/attapulgite composite shape-stabilized phase change material was from 32.3°C to 43.7°C,the latent heat of phase change is 64.64 J?g^-1.By studying the properties of attapulgite composite shape-stabilized phase change materials and lauric acid/attapulgite composite shape-stabilized phase change material for cement-based materials,it is found that the mechanical properties,bulk density and thermal conductivity of cement-based materials decrease with the increase of the content of two type of composite shape-stabilized phase change materials,but the specific heat capacity is increased.The incorporation of attapulgite composite shape-stabilized phase change material reduced the bulk density of the phase change energy storage mortar decreased by9.1%,the thermal conductivity decreased by 49.8%,and the specific heat capacity decreased by 40.9%.With the addition of lauric acid/attapulgite composite shape-stabilized phase change material,the flexural strength and compressive strength of cement paste decreased by 33.3%and 29.4%respectively,cement mortar decreased by 37.5%and 47.3%,bulk density decreased by 9.6%,thermal conductivity decreased by 32.4%,and specific heat capacity increased.53.3%.It is found that the mechanical properties,thermal conductivity and heat storage coefficient of phase change energy storage cement-based materials can be increased when graphene is 0.05wt.%,but the effect on the bulk density and specific heat capacity of phase change energy storage mortar are not significant.