Study On Polyurethane Based Form-Stable Phase Change Composite With High Energy Density

In order to prevent solid-liquid phase change materials (PCMs) from leaking during use, researchers usually composite solid-liquid PCMs with supporting materials to prepare phase change composites through physical or chemical method. However, although traditional supporting materials, such as polyethylene, silicon dioxide, expanded and metal foam, can absorb and restrain amount of solid-liquid PCMs, prevent the liquid from flowing freely, and finish the form-stable phase change process, they make the effective content of PCMs down, which results in the obvious decrease of phase change enthalpy of PCMs. In this thesis, kinds of phase change polyurethane, which can act as supporting materials in phase change composites, were designed and prepared, and phase change composites that were made of polyurethane and solid-liquid PCMs were obtained to reduce the impact to the encapsulation of solid-liquid PCMs.Form stable PCM of linear polyurethane structure was obtained in this thesis, in which PEG serves as soft segment, TDI and azo dyes serve as hard segment, this material has good heat setting effect, high thermostability, except for the function of visible light absorption and photothermal conversion. Hexadecanol/linear polyurethane phase change composite was obtained by mixing this linear polyurethane with hexadecanol through solution mixing method, FTIR, XRD, DSC, TG, photothermal conversional test and heating test show that, hexadecanol and linear polyurethane were physically mixed, hexadecanol content could reach 63.8 wt% without leakage, along with the phase change enthalpy of 229.5 J/g, this material has high photothermal conversion efficiency and good thermostability, which can meet the application requirement.Form stable PCM of crosslinking polyurethane structure was obtained in this thesis, in which PEG serves as soft segment, TTI serves as hard segment, this material has 3-D net structure, strong mechanical properties and good heat setting effect. Paraffin/crosslinking polyurethane phase change composite could be obtained by blending paraffin and crosslinking polyurethane, in which polyurethane acts as supporting material. FTIR and XRD test showed that, no chemical reaction occurred between paraffin and polyurethane, blending didn't affect crystal habit of PEG and paraffin, either. It can be known from SEM image that, paraffin was absobed on PEG chains, filling the lacuna of 3-D net structure. DSC test indicates that, paraffin content could reach 74 wt% without leakage, along with phase change enthalpy of 210.6 J/g.A kind of form-stable phase change composites consist of above crosslinking polyurethane and PEG (Mn=10000) were obtained in this thesis, in which crosslinking polyurethane serves as supporting materials. After various measurements, it is clear that this kind of composites were excellent in energy storage, form stability, thermostability and other properties.