Preparation And Properties Of Wood/capric Acid-palmitic Acid Eutectic Mixture Form-stable Phase Change Material

With the rapid development of the global economy,these issues such as energy shortage,low energy efficiency,and environmental pollution have attracted more and more attention.The researchers found that phase change materials can use their phase changes to achieve energy absorption and release.Therefore,these problems of energy shortage,low energy efficiency,and environmental pollution were alleviated.In this paper,wood and modified wood were used as supporting materials,and the capric-palmitic acid(CA-PA)eutectic mixture was used as phase change material.The wood(wood and modified wood)/CA-PA mixture form-stable phase change material(FSPCM)was prepared by ultrasonic treatment,vacuum adsorption,and ultrasonic and vacuum composite methods.The FSPCM was characterized by microscopic morphology,molecular structure,and thermal properties,etc.The main research contents are as follows:(1)According to the lowest eutectic theory,two kinds of single fatty acid phase change materials of capric acid and palmitic acid were selected as raw materials,the mass ratio was determined by Schrader formula calculation and experiment.Then CA-PA eutectic mixture was prepared by melting and then ultrasonic method.The results showed that the mass ratio is 84.5:15.5.(2)The paulownia wood(Paulownia elongata S.Y.Hu),fir(Cunninghamia lanceolata(Lamb.)Hook.),poplar(Populus SPP),and pine(Pinus SPP)were selected as the supporting materials of CA-PA eutectic mixture,and the FSPCMs were prepared by vacuum adsorption,ultrasonic treatment,and vacuum ultrasonic composite methods.The form-stabled effects of different types of wood on fatty acids were contrasted and analyzed.The results showed that the combination of pine and CA-PA eutectic mixture was used to prepare the best performance FSPCM by the vacuum adsorption method.(3)The fir and pine were modified treatment using Na Cl O₂ and the composite solution of Na OH and Na₂SO₃ and then H₂O₂ peroxide.These treated woods were used as supporting material of CA-PA eutectic mixture.Thses two FSPCMs were prepared by vacuum adsorption method.Finally,the performance of the sample is further characterized and analyzed.The results showed that the fir modified by the composite solution of Na OH and Na₂SO₃ and then H₂O₂ peroxide has great properties.The SEM showed that the porous honeycomb-like structure of the fir was well-preserved,and the organized cell wall became thinner,which caused the hole larger.Microscale pores were generated in the cell wall.It was also observed that the CA-PA eutectic mixture was adsorbed into the pore structure of the fir.The FTIR results showed that the C=O of the fir treated with the composite solution of Na OH and Na₂SO₃ and then H₂O₂ peroxide disappeared.Also suggesting that the modified fir is physically combined with CA-PA eutectic mixture,and no chemical reaction occurred.Therefore,a good phase change performance can be maintained.The DSC results showed that the latent heat of phase change for modified fir is much larger than that of unmodified due to the higher adsorption rate of CA-PA eutectic mixture.The TG results showed that the introduction of modified fir results in a certain residual quality of the FSPCM.It was further indicated that the thermal stability of the FSPCM is better than that of the pure phase change material.The results of thermal cycling showed that the thermal properties and chemical structure of the FSPCM have not changed greatly after 100thermal cycles.It indicated that the thermal reliability of the FSPCM is very great.In summary,the pine and the fir modified by the composite solution of Na OH and Na₂SO₃ and then H₂O₂ peroxide conbined with the CA-PA eutectic mixture can prepare FSPCMs with great properies using a vacuum impregnation method,which has great application potential in the field of construction.The theoretical study of this paper will be phase change energy storage.The application of materials in construction timber provided a new research idea.