Browsing by Author "Hobson, Jose"
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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 MXene multi-functionalization of polyrotaxane based PCMs and the applications in electronic devices thermal management.(Nano Materials Science, 2024) Yin, Guang-Zhong; López, Alba Marta; Collado, Ignacio; Vázquez López, Antonio; Ao, Xiang; Hobson, Jose; Prolongo, Silvia G.; De-Yi, WangThe aim of this work was to improve the thermal conductivity and electromagnetic shielding of the leakage proof phase change materials (PCMs), in which a polyrotaxane (PLR) was used as a support material to encapsulate PEG 1k or PEG 6k and MXene as multi-functional filler. The PCMs can be processed conveniently by a hot press and the PEG 1k containing samples showed excellent flexibility. We conducted a systematic evaluation of the phase transition behavior of the material, thermal conductivity and electromagnetic shielding performance tests. Notably, the PCMs achieved a high enthalpy values (123.9–159.6 J/g). The PCMs exhibited an increase of 44.3 %, and 137.5 % in thermal conductivity values with higher MXene content (5 wt%) for PLR-PEG6k and PLR-PEG1k, respectively, and show high shape stability and no leakage during and after phase transition. The introduction of MXene can significantly improve the electromagnetic shielding performance of PCM composites. Typically, higher conductive samples (samples which contain high MXene contents) offer a higher EMI SE shielding, reaching a maximum of 4.67 dB at 5.6 GHz for PLR-1K-MX5. These improvements solve the main problems of organic PEG based PCMs, thus making PLR-PEG-MXene based PCMs good candidates for thermoregulators of both solid-state disks and smart phone. It is worth pointing out that the sample PLR-1k-MX5 can decrease 4.3 °C of the reference temperature during cellphone running. Moreover, the temperature of the protecting sheet in the simulated solid state disk with PCM was significantly lower (showing a decreasing of 7.9 °C) compared with the blank sample.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 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 Polyrotaxane: New generation of sustainable, ultra-flexible, form-stable and smart phase change materials.(Energy Storage Materials, 2021) Yin, Guang-Zhong; Hobson, Jose; Duan, Yanyan; De-Yi, WangThe development of thermal energy storage materials is the most attractive strategy to harvest the solar energy and increase the energy utilization efficiency. Phase change materials (PCMs) have received much attention in this research field for several decades. Herein, we reported a new kind of PCM micro topological structure, design direction, and the ultra-flexible, form-stable and smart PCMs, polyrotaxane. The structure of polyrotaxane was fully confirmed by 1H nuclear magnetic resonance, attenuated total reflection-fourier transform infrared and X-ray diffraction. Then the tensile properties, thermal stability in the air, phase change energy storage and shape memory properties of the films were systematically analyzed. The results showed that all the mechanical performance, thermal stability in air and shape memory properties of polyrotaxanes were enhanced significantly compared to those of polyethylene oxide (PEO). The form stability at temperatures above the melting point of PEO significantly increased with the α-CD addition. Further with the high phase transition enthalpy and excellent cycle performance, the polyrotaxane films are therefore promising sustainable and advanced form-stable phase change materials for thermal energy storage. Notably, its ultra-high flexibility, remolding ability and excellent shape memory properties provide a convenient way for the intelligent heat treatment packaging of complex and flexible electronic devices. In addition, this is a totally novel insight for polyrotaxane application and new design method for form-stable PCMs.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 Synergistic Effect of Cerium Oxide for Improving the Fire-Retardant, Mechanical and Ultraviolet-Blocking Properties of EVA/Magnesium Hydroxide Composites.(Materials, 2022) Hobson, Jose; Yin, Guang-Zhong; Yu, Xiaoli; Zhou, Xiaodong; Gonzalez Prolongo, Silvia; Ao, Xiang; De-Yi, WangRare earth oxide particles have received important attention in recent years, and due to the wide diversity of promising applications, the need for this kind of material is predicted to expand as the requirements to use the current resources become more demanding. In this work, cerium oxide (CeO2) was introduced into ethylene-vinyl acetate (EVA)/magnesium hydroxide (MDH) composites for enhancing the flame retardancy, mechanical properties and anti-ultraviolet aging performance. The target EVA/MDH/CeO2 composites were prepared by extrusion and injection molding, and the effects of the addition of the CeO2 were explored by thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), limiting oxygen index (LOI), UL-94, cone calorimetry test, and anti-ultraviolet aging test. Typically, the incorporation of the CeO2 allows a significant increase of the elongation at break and Young’s modulus compared with EVA/MDH by 52.25% and 6.85%, respectively. The pHRR remarkably decreased from 490.6 kW/m2 for EVA/MDH to 354.4 kW/m2 for EVA/MDH/CeO2 composite. It was found that the CeO2 presents excellent synergism with MDH in the composites for the anti-UV properties in terms of mechanical properties preservation. Notably, the combination of CeO2 with MDH is a novel and simple method to improve the filler–polymer interaction and dispersion, which resulted in the improvement of the mechanical properties, flame retardancy and the anti-ultraviolet aging performance of the composites.