Study On Optimal Preparation And Functionalization Of Phase Change Capsule Materials

The rapid economic growth has led to an aggravated shortage of fossil fuels,and the world needs to find alternative energy sources or methods and materials to improve energy efficiency.As an ideal heat storage material,phase change material has attracted the attention of many researchers.The phase change material(PCM)has a large heat storage density,can maintain a constant temperature level during the phase change and is reversible when storing and releasing energy,which has a high use value.However,phase change materials may leak during actual use,resulting in limited applications.Effective encapsulation of phase change materials can avoid this problem.The phase change capsule material can use the heat absorption and release of the phase change material in the phase change process for energy storage and release.It has high research value in solar energy storage applications,building energy conservation,textile industry,military,and other energy storage fields.There are still some theoretical and practical problems that need to be studied and resolved in depth.First,making better use of the energy of phase change materials is the main direction of current research.Secondly,the functionalization of PCMs makes materials have a wider application scenario.The main content of this work is the optimized preparation and functionalization of phase change capsule materials.The details are as follows:1.We prepared n-octadecane@poly2,3,4,5,6-pentafluorostyrene(PPFS)nanocapsules by suspension polymerization.Analyze by characterization methods such as FTIR,XRD,SEM-EDS,DSC,TGA,and LSA.It is found that when the mass ratio of PPFS and n-octadecane is1:2,the enthalpy value and encapsulation rate can reach 171.8±2.2 J·g^-1 and 76.1±1.0%.The nanocapsules also have good oleophobic and hydrophobic properties measured by contact angle measuring instruments.This work provides an innovative strategy for the design and development of phase change nanocapsules and has good application potential.2.We use calcium carbonate to encapsulate n-octadecane to prepare n-octadecane@Ca CO₃phase change microcapsules.By changing the reaction core-shell ratio,rotation speed,temperature,emulsifier type,and concentration,and other process parameters,we explore the effect the influence of the microscopic morphology and thermal properties of the phase-change microcapsules and the characterization of various thermal properties of the product were performed,and the optimal reaction conditions for preparing the phase-change microcapsules were obtained by analysis.When the core-to-shell ratio is 1:1,the speed is 800rpm,the temperature is 45?,the emulsifier is SDBS,and the concentration is 0.075 mol/L,the enthalpy and encapsulation rate of the preparation phase change microcapsules are 92.3 J·g^-1,respectively and 41.7%.The thermal conductivity is 5.91 times higher than that of n-octadecane.3.By adsorbing nano-Fe₃O₄ particles on the paraffin wax surface coated with calcium carbonate,magnetic functional phase change microcapsule materials can be prepared.When the content of Fe₃O₄ nanoparticles is 0.08%,the saturation magnetization reaches 1.03 emu/g,and the enthalpy value is 80.2 J·g^-1.All tests show that the prepared magnetic phase change material microcapsules have excellent dual characteristics of magnetic properties and phase change.Magnetized microcapsule phase change materials provide new research ideas for encapsulated phase change materials,and intelligent phase change materials that are easy to manipulate will attract more people's attention.