Browsing by Author "Yang, Xiao-Mei"
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Item Bio-based poly (glycerol-itaconic acid)/PEG/APP as form stable and flame-retardant phase change materials(Composites Communications, 2022) Yin, Guang-Zhong; Yang, Xiao-Mei; Hobson, Jose; Marta López, Alba; De-Yi, WangWith the improvement of people's living level, smart home and comfortable life put forward novel and highly scientific requirements for building materials and home environment. Environmental protection, renewability, processing convenience and use safety (non-toxic/fire safety) are all core indicators that need to be considered in an all-round way in the process of material design. In this work, we used a simple and efficient green process by blending ammonium polyphosphate (APP) and poly (glycerol-itaconic acid) loaded polyethylene glycol (PEG) to prepare fire safe phase change materials (PCMs). The flame retardancy, phase change performance and thermal response behavior (including form stability, thermal conductivity, cycle stability, and latent heat etc.) were systematically characterized. The results showed that limiting oxygen index (LOI) increased significantly with the increase of APP content. Typically, when the filling amount of APP reached 15 wt%, the LOI value increased from 21.6% to 28.7%, vertical testing reached UL-94 V0 rating and the pHRR decreased by 36.15%. The as-prepared PCMs show excellent form stability, and the enthalpy of phase change keeps higher than 70 J g−1, which is at the high level as that of same kinds of PCMs. Notably, due to its high preparation efficiency for PCM fabrication and the profiles of all bio-based supporting matrix, solvent-free pathway, mild curing temperature, and fire safety, it is expected to be effectively applied in building for the thermal regulation.Item Graphene Functionalization of Polyrotaxane-Encapsulated PEG-Based PCMs: Fabrication and Applications.(Advanced Materials, 2023) Yin, Guang-Zhong; Yang, Xiao-Mei; López, Alba Marta; García Molleja, Javier; Wang, Mei-Ting; De-Yi, WangPhase change materials (PCMs) have received much attention regarding the thermal regulation of electronic devices. However, the main limitations of using organic PCMs are the low thermal conductivity and leakage during the phase change process. This work aims to improve these limitations to increase the thermal conductivity of the leakage-proof PCM formed by a polyrotaxane that serves as a support material to encapsulate PEG. For this purpose, different contents of graphene nanoplatelets (GNP) are blended. To facilitate its postindustrial production and to meet ecological standards, the synthesis of this PCM is simple and only using water as a solvent. The PCMs can be thermally processed conveniently by a hot press. Furthermore, the PCMs achieve high enthalpy values (132.9–142.9 J g−1) due to the action of GNPs as thermally conductive fillers. The PCMs exhibited an increase of 60–257% in thermal conductivity values with higher GNP content, and show great shape stability and no leakage during phase change. These improvements solve the main problems of organic PCMs, thus making PLR-PEG-GNP-based materials a good candidate for use as thermal energy storage materials in industrial applications as thermoregulators of solid-state disks or realizing the “shaving peaks and filling valleys” effect for thermoelectric generators.Item Highly thermal conductive Boron Nitride/Polyrotaxane encapsulated PEG-based phase change materials.(European Polymer Journal, 2023) Yin, Guang-Zhong; Yang, Xiao-Mei; López, Alba Marta; García Molleja, Javier; Vázquez-López, Antonio; De-Yi, WangIn this work, we tried to overcome the typical limitations of phase change materials (PCMs), namely, leakage and low thermal conductivity. To realize the leakage proof PCM, a polyrotaxane (PLR) was selected as a support material to encapsulate Polyethylene glycol (PEG) 1 k. Subsequently, different contents of Boron Nitride (BN) were blended to enhance the thermal conductivity of PLR/PEG matrix. The PCMs created in this work achieves a high thermal performance with enthalpy values (91.2–123.5 J/g) and high flexibility and shows a great shape stability and no leakage and shape change during its phase transition. Due to the action of BN as a multifunctional filler, the PCMs also experienced an increase of 186.7% to 806.7% in thermal conductivity values, and enhanced flame retardancy (with decrease of 16.6% for pHRR and 25.5% for THR). These improvements solve the main problems of organic PCMs thus making PLR-PEG-BN based materials a good candidate to be used as thermal energy storage material in industrial applications. For the exact application cases, it showed obvious Peak Shaving and Valley Filling for thermoelectric generator and heat regulation for the smart phone.Item Phytic acid as a biomass flame retardant for polyrotaxane based phase change materials.(Journal of Energy Storage, 2022) Yin, Guang-Zhong; Yang, Xiao-Mei; Díaz Palencia, José Luis; Hobson, Jose; López, Alba Marta; De-Yi, WangPetrochemical resources are facing depletion and human long-term survival needs sustainable development. In this era, it is very important to develop new sustainable phase change materials (PCMs), because it has shown great application value in the effective utilization of industrial waste heat, solar energy harvesting, and electronic heat treatment. In this work, we reported a biomass phytic acid (PA) modified polyrotaxane (PLR) as PCMs for thermal management. The tensile performances, fire safety, phase transition performances of the PCMs were investigated. It is found that all the tensile properties, char residual, and fire-safety of PLR can be enhanced remarkably by introduce of PA. Typically, the Young's modulus, yielding strength and tensile strength of the PLR were 826.7 MPa, 14.2 MPa and 14.2 MPa, respectively, and significantly increased to 1527.4 MPa, 22.1 MPa, and 24.0 MPa respectively, with the addition of 10 wt% of PA. Elongation (>783 %) for all modified PCMs was gradually increased with the increase of PA contents. Thermal analysis shows that the fire safety of PLR is significantly improved. Specifically, for the best sample PLR-PA30, the pHRR could decrease by 54.2 %, THR decreased by 34.0 %; and the LOI increased from 20.8 % to 28.2 %. The PCMs showed the perfect form stability and leakage-proof performance, enhanced thermal conductivity and outstanding cycle properties. Notably, its biomass source, and high flexibility, enhanced fire safety and completely green pathway may provide a practical way for the highly flexible and sustainable packaging of electronic devices for heat treatment.Item PLA aerogel as a universal support for the typical organic phase change energy storage materials.(Journal of Energy Storage, 2023) Yin, Guang-Zhong; Yang, Xiao-Mei; López, Alba Marta; Ao, Xiang; Wang, Mei-Ting; García Molleja, Javier; De-Yi, WangWe first prepared Polylactic acid (PLA) aerogels with high porosity based on a facile and efficient thermal induced phase separation technique. In view of the excellent internal nano structure of PLA aerogel, high porosity and suitable interfacial affinity, it was selected as a support material to encapsulate four common organic phase change materials (PCMs), thereby preparing anti-leakage, shape-stable and sustainable PCMs with ultra-high latent heat (178.9–224.9 J g−1). PLA aerogel encapsulated PCMs perform high enthalpy efficiency (>92 %), which may benefit from the highly internal compatible nanostructure of PLA. Thermally conductive fillers (Boron nitride and Graphene nanoplatelet) were introduced to improve thermal conductivity. An important factor of PLA aerogel as a universal encapsulation matrix is analyzed based on the solubility parameters and Flory-Huggins parameters. The application cases of smart container and thermal regulation in confined spaces further prove the practical application value in the thermal regulation and energy saving area.Item Polyrotaxane based leakage-proof and injectable phase change materials with high melting enthalpy and adjustable transition temperature.(Chemical Engineering Journal, 2022) Yin, Guang-Zhong; López, Alba Marta; Yang, Xiao-Mei; Ao, Xiang; Hobson, Jose; De-Yi, WangIn this work, a series of advanced phase change materials (PCMs) were fabricated by using polyrotaxane (PLR) as supports for encapsulating poly (ethylene glycol) (PEG). Phase-change enthalpy is mainly regulated by the PEG contents, whereas phase change temperature is controlled by PEG molecular weight. All PCMs have good form stabilities due to the good compatibility between PLR and PEG, and supporting ability of PLR. Given that the PLR support itself has phase-transition properties, the resulting composites have high phase change enthalpies (116.1–162.2 J g -1) and very high enthalpy efficiency (>100%). It is a green and efficient preparation method because the whole preparation process did not involve organic solvents, and the material was prepared at room temperature. In addition, the obtained PCMs can be easily extruded and re-molded, which provides technical premise and convenience for the large-scale applications. As a typical application example, the PCMs showed its significant advantages in simulated solid-state disk model temperature regulation, which fully demonstrates the practical and superior application value of the PCMs in the field of thermal management for electronic devices.Item Recent Advances in Flame Retardant and Mechanical Properties of Polylactic Acid: A Review.(Advanced Materials, 2023) Yang, Xiao-Mei; Qiu, Shuang; Yusuf, Abdulmalik; Sun, Jun; Zhai, Zhongjie; Zhao, Junhuan; Yin, Guang-ZhongThe large-scale application of ecofriendly polymeric materials has become a key focus of scientific research with the trend toward sustainable development. Mechanical properties and fire safety are two critical considerations of biopolymers for large-scale applications. Polylactic acid (PLA) is a flammable, melt-drop carrying, and strong but brittle polymer. Hence, it is essential to achieve both flame retardancy and mechanical enhancement to improve safety and broaden its application. This study reviews the recent research on the flame retardant functionalization and mechanical reinforcement of PLA. It classifies PLA according to the type of the flame retardant strategy employed, such as surface-modified fibers, modified nano/micro fillers, small-molecule and macromolecular flame retardants, flame retardants with fibers or polymers, and chain extension or crosslinking with other flame retardants. The functionalization strategies and main parameters of the modified PLA systems are summarized and analyzed. This study summarizes the latest advances in the fields of flame retardancy and mechanical reinforcement of PLA.Item Shape-stable and smart polyrotaxane-based phase change materials with enhanced flexibility and fire-safety.(European Polymer Journal, 2022) Yin, Guang-Zhong; Marta López, Alba; Yang, Xiao-Mei; Ye, Wen; Xu, Baoyun; Hobson, Jose; De-Yi, WangItem Sodium alginate and Chitosan aided design of form-stable Polyrotaxane based phase change materials with ultra-high latent heat.(International Journal of Biological Macromolecules, 2022) Yin, Guang-Zhong; Yang, Xiao-Mei; López, Alba Marta; Wang, Mei-Ting; Ye, Wen; Xu, Baoyun; De-Yi, WangWe prepared a series of highly porous Polyrotaxane/sodium alginate, and Polyrotaxane/Chitosan foam alloys according to a sustainable pathway by using water as the only solvent. The foam alloys were further used as supporter materials for poly (ethylene glycol) (PEG) encapsulation, to fabricate shape-stable bio-based phase change materials (PCMs). The pore morphology and the internal interface between PEG and foam alloys were characterized by scanning electron microscope (SEM). Due to the good compatibility between foam alloys and PEG, the PCM performed perfect anti-leakage properties. The introduction of sodium alginate or Chitosan ensures the shape stability of the PCMs during the phase transition. The PCMs performed good cycle stability and showed ultra-high latent heat (171.6 J g−1–189.5 J g−1). Finally, we compared the typical indicators of this work with those reported in the literature, and the comparison highlighted that the present PCMs have the significant advantages: high melting enthalpy, convenient preparation and outstanding sustainability. Notably, the work provided a sustainable idea for the design of anti-leakage and shape-stable PEG-based PCMs.