Flexible and Mechanically Enhanced Polyurethane Composite for γ-ray Shielding and Thermal Regulation

Abstract

Microencapsulation of paraffin with lead tungstate shell (Pn@PWO) shows the drawbacks of low wettability and poor leakage-proof property and thermal reliability, restricting the application of phase change microcapsules. Herein, a novel paraffin@lead tungstate@silicon dioxide double-shelled microcapsule (Pn@PWO@SiO 2 ) has been successfully constructed by the emulsion-templated interfacial polycondensation and applied in the waterborne polyurethane (WPU). The results indicated that a SiO 2 layer with controlled thickness was formed on the PbWO 4 shell. The Pn@PWO@SiO 2 microcapsules have exhibited superior leakage-proof properties and thermal reliability through doubleshelled protection, and the leakage rate decreased by at least 54.11% compared to that of Pn@PWO microcapsules. The SiO 2 layer with abundant polar groups ameliorated the wettability of microcapsules and the interfacial compatibility between microcapsules and the WPU matrix. The tensile strength of WPU/Pn@ PWO@SiO 2 -2 composites reached 10.98 MPa, which was over 7 times greater than that of WPU/Pn@PWO composites. In addition, WPU/Pn@PWO@SiO 2 -2 composites with a latent heat capacity of over 41 J/g exhibited efficient phase change stability and γ-ray shielding properties. Also, the mass attenuation coefficients reached 1.38 cm 2 /g at 105.3 keV and 1.12 cm 2 /g at 86.5 keV, respectively. These properties will greatly promote the application of WPU/Pn@PWO@SiO 2 composites into γ-ray-shielding devices with thermal regulation.

Poly(ethylene glycol)-Based Reprocessed Solid–Solid Phase Change Materials with Dynamic Semi-interpenetrating Network for Efficient Energy Storage and Thermal Management

“…Therefore, the optimization of RSSPCMs in thermal regulation and thermal management for the problem of thermal energy charging and discharging processes is crucial. 17 The nonisothermal phase change behaviors of RSSPCM-3 are investigated with the DSC technique, and its thermal energy storage and release properties at different temperatures are tested, as shown in Figure 4. The 3D heat flow diagrams obtained at various ramp rates of the temperature are depicted in Figure 4a.…”

“…14−16 Severe leakage problems constrain the application of conventional solid−liquid PCMs. To alleviate this problem, form-stabilized PCMs (FSPCMs) have been prepared by microencapsulation, 17 physical adsorption, or chemical crosslinking techniques. 18−20 In particular, FSPCMs are obtained by introducing phase change components into the cross-linked polymer network through covalent bonding, which improves the leakage resistance and mechanical strength.…”

“…Severe leakage problems constrain the application of conventional solid–liquid PCMs. To alleviate this problem, form-stabilized PCMs (FSPCMs) have been prepared by microencapsulation, physical adsorption, or chemical cross-linking techniques. − In particular, FSPCMs are obtained by introducing phase change components into the cross-linked polymer network through covalent bonding, which improves the leakage resistance and mechanical strength. However, covalently bonded cross-linked PCMs have a major disadvantage in that the three-dimensional cross-linked network is permanent and suffers from the problem of difficult recycling. − Currently, the commonly used treatment methods are incineration and earth burial, which cause a huge waste of resources and environmental pollution and are thus not conducive to environmental friendliness.…”

Paraffin@poly(methyl methacrylate) Phase Change Microcapsules for Thermal Energy Storage and Temperature Regulation

“…Hence, PCMs exhibit tremendous potential for applications in buildings, smart textiles, thermal management for electronics/batteries, solar energy conversion, etc. [7] PCMs also have many shortcomings restricting their practical applicability, such as easy leakage, low thermal conductivity, volume expansion and phase separation. [8][9][10][11] In order to overcome the above limitations of PCMs, three methods of encapsulating PCMs are commonly employed, namely polymer shape-stabilized PCMs, [12] adsorption shapestabilizing of porous materials [13] and encapsulation shapestabilizing of microcapsules.…”

“…PCMs can reversibly absorb/release a large amount of latent heat during the phase‐change process under approximately constant temperature, [5,6] which has the advantages of high energy storage density, suitable phase‐transition temperature, and good chemical stability. Hence, PCMs exhibit tremendous potential for applications in buildings, smart textiles, thermal management for electronics/batteries, solar energy conversion, etc [7] …”