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利用聚乙二醇(PEG)为相变材料、以羟丙基甲基纤维素为分子骨架,采用4,4-二苯基甲烷二异氰酸酯作为交联剂,用化学接枝法成功合成了一种新型复合相变材料。采用红外光谱、差示扫描量热仪、热重仪、扫描电镜和X射线衍射仪对该复合相变材料的化学结构、相变性能、热稳定性、微观形貌和晶体结构等性能进行了表征。结果表明:该复合相变材料的相变过程表现为固-固相变的性质,其相变温度在309~323.2K范围内,相变焓值在89.8~106.8J/g之间。可见,通过化学接枝法得到的复合相变材料具有较好的相变行为,且克服了聚乙二醇在相变过程中的泄露问题。 相似文献
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通过分子设计,把具有固-液相变性能的聚乙二醇单甲醚(MPEG)的端羟基改性为具有乙烯基碳碳双键的大单体,形成一种可以与任意含有乙烯基双键的骨架材料进行自由基共聚合的具有高相变焓的固-固相转变单体材料。运用傅立叶变换红外光谱(FT-IR)和核磁共振氢谱(1H-NMR)表征了大单体的结构,采用差示扫描量热法(DSC)、广角X射线散射仪(WAXD)和偏光显微镜(POM)、热失重(TG)表征并分析了MPEG的热性能及其结晶情况。结果表明,这种新型单体具有稳定的分子结构、良好的结晶性能、高相变焓,热稳定性良好。从而为聚乙二醇类的固-液相变材料在固-固相变材料的应用领域中开辟了一条新的途径。 相似文献
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一种含有乙烯基具有固-固相变性能的大单体的制备及表征EI 总被引:3,自引:0,他引:3
通过分子设计,把具有固-液相变性能的聚乙二醇单甲醚(MPEG)的端羟基改性为具有乙烯基碳碳双键的大单体,形成一种可以与任意含有乙烯基双键的骨架材料进行自由基共聚合的具有高相变焓的固-固相转变单体材料。运用傅立叶变换红外光谱(FT-IR)和核磁共振氢谱(1H-NMR)表征了大单体的结构,采用差示扫描量热法(DSC)、广角X射线散射仪(WAXD)和偏光显微镜(POM)、热失重(TG)表征并分析了MPEG的热性能及其结晶情况。结果表明,这种新型单体具有稳定的分子结构、良好的结晶性能、高相变焓,热稳定性良好。从而为聚乙二醇类的固-液相变材料在固-固相变材料的应用领域中开辟了一条新的途径。 相似文献
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采用乳液法以低分子量聚乙二醇和酰氯化硬脂酸的酯化反应制备了聚乙二醇双硬脂酸酯,以其为核,以二苯甲烷二异氰酸酯与乙二胺的缩合物为壳,制备具有相变功能的核壳结构材料。使用FT-IR、DSC、TG以及偏光显微镜等方法对酯化产物和核壳结构材料进行了表征。PEG200双硬脂酸酯固-液相变温度在30℃-35℃,相变焓为95 J/g。核壳材料相变焓为32 J/g。 相似文献
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通过在丙烯酰胺聚合反应中加入聚乙二醇的方法制得的聚乙二醇(PEG)/聚丙烯酰胺(PAAm)相变材料具有固-固相转变的性质。对聚乙二醇及五种相变材料分别进行不同速率的非等温DSC测试,采用K iss inger和O zaw a两种动力学模型研究了非等温固-固相变动力学,计算了固-固相变过程的活化能和反应级数,两种方法求得的表观活化能Ea值相一致。 相似文献
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一种新型的相变储能功能高分子材料 总被引:43,自引:0,他引:43
介绍了本实验室制备的一种新型的固态相变材料,叙述了它的合成方法,讨论了该类材料的相变机理及其特点等,结果表明,该类新型固态相变材料不仅相变焓大,而且热稳定性有明显改善,各项综合性能优异,具有很大的使用价值和发展前途。 相似文献
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Huizhi Yang Ruiyao Chu Chunhua Ge Fanghui Zhu Rui Liu Xiangdong Zhang 《Advanced Engineering Materials》2023,25(20):2300720
Currently, the majority of composite phase change materials (PCM) are only available in solid-phase environments. Therefore, it is important to prepare composite PCM with photothermal conversion capacity, high thermal conductivity, and stability in both solid and aqueous phase conditions. Herein, a composite PCM with high photothermal conversion storage efficiency (92.6%), high energy storage density (147.6 J g−1), and high thermal conductivity (1.19 W m−1 K) is prepared using poly(acrylamide-co-polyacrylic acid) copolymer (PAAAM) as the supporting material, boron nitride as the high thermal conductivity filler, and carboxyl-rich carbon as the photothermal conversion agent and key bridge. With the help of the characteristics of PAAAM, although the PAAAM chain is swollen not broken, it still maintains cross interconnection with PCM in the water-phase environment, which has excellent encapsulation performance in both the water/solid phase environment. This provides another option for broadening the application of PCM in aqueous solvent conditions. 相似文献
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针对相变材料在实际应用过程中交替存在升温液化和降温固化的复杂传热过程,采用JW-Ⅲ建筑材料热流计式导热仪,分别对升温和降温过程中处于固态、混合态、液态的新型复合相变材料导热性能进行了测试和分析。研究结果表明,复合相变材料在加热和冷却过程中的导热系数随温度的变化存在明显的规律性差异,导热系数在混合态时差值达到20%;升温过程中,复合相变材料在混合态和液态时的导热系数值相差不大,但与固态时相比有明显减小;降温过程中,在液-固相变的过程中导热系数随温度减小而增大,有利于加速相变材料的固化。 相似文献
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De Santis R Ambrogi V Carfagna C Ambrosio L Nicolais L 《Journal of materials science. Materials in medicine》2006,17(12):1219-1226
Microencapsulated paraffin based phase change material (PCM) have been incorporated into Poly(methyl-methacrylate) (PMMA)
matrix in order to enhance the thermo-mechanical properties. Calorimetric and mechanical analyses are carried out and the
thermo regulating potential of PMMA/PCM composites is investigated. Results indicate that the PCM phase has a negligible effect
on the glass transition temperature of the PMMA matrix, and the thermal regulating capability spans around body temperature
absorbing or releasing a thermal energy up to 30 J/g. One of the effect of the PCM phase into the cement is the reduction
of the peak temperature developed during the exothermal reaction. 相似文献
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人类在面临化石能源枯竭的同时,对能量的利用率依然还停留在较低的水平。因此,在大力发展新能源的同时,着力研发节能环保新材料新技术具有十分重要的意义。相变材料(phase-change materials,PCM)是一种节能环保的储能材料,它在蓄热与温控等领域具有大规模商业应用的潜力。本文首先对相变储能材料的基本特征、工作原理以及分类等方面作了简要的介绍;并就相变储能材料在温控与蓄热等领域的应用与发展情况进行了具体的分析,指出了PCM的性能是制约其深入广泛应用的主要技术障碍。在此基础上,详细评述了PCM存在的主要问题以及针对这些问题开展的相关研究工作和最新发展动态,指出通过功能复合等新技术优化材料性能、设计新材料体系、拓展新的应用领域将是相变储能材料未来的主要发展方向。 相似文献
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This study aimed to investigate the mechanical properties of concrete containing solid–liquid phase-change material (PCM) and focused on two key factors. First, a systematic study on the mechanical performance of PCM-modified concretes was conducted, including compressive, elastic modulus, and shrinkage tests. Second, because PCM provides high latent heat during the solid–liquid phase change, the effects of the solid phase and liquid phase on the mechanical properties of concrete were also explored. Results of this study showed that the solid–liquid phase of PCM affected the mechanical properties of concrete. For example, the compressive strength of 10% PCM concrete in solid phase (23 °C) and liquid phase (40 °C) at 28 days was 29.30 and 19.57 MPa, respectively. In addition, with increasing PCM content, the mechanical properties were degraded. For example, 10, 20, and 30% of PCM content lowered the compressive strength by 35.4, 58.4, and 74.3%, respectively. Therefore, concrete with PCM may not be suitable for structural elements. However, PCM is an important solution for optimizing energy consumption in modern buildings. It can absorb or emit large amounts of heat to store or release thermal energy. These properties can be used to control building temperatures resulting in energy saving and carbon reduction. 相似文献
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This paper discusses the use of phase change materials (PCM) in concrete pavement as a method to store energy which can be used as a heat source during cooling events to melt ice/snow. The experimental program includes: (1) use of low-temperature differential scanning calorimetry to evaluate thermal properties of PCM, and (2) use of large-scale concrete slabs containing PCM to evaluate the ability of the PCM concrete to melt snow on the surface of the concrete pavement. The temperature in the concrete slabs and the snow melting rate were monitored as quantitative measurements of the efficiency of the PCM in the concrete. In addition, time-lapse images were taken. Two approaches were used to incorporate PCM in concrete: placing the PCM in lightweight aggregate (LWA) which was then mixed into the concrete, and placing the PCM in embedded metal pipes embedded in the slab during concrete casting. In this study, paraffin oil was use as a PCM that is effective in releasing heat near the freezing temperature of PCM when the PCM undergoes a phase transformation from liquid to solid. The heat released during the phase transformation can melt ice and snow on the concrete pavement surface. The results indicate that incorporating PCM in concrete pavement is not only feasible, but also practical. 相似文献
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Hyperbranched polyurethane solid–solid phase change material (HB-PUPCM) has been prepared via a two-step process. The phase
transition behaviors and morphologies of these HB-PUPCM films were investigated using differential scanning calorimetry (DSC),
wide-angle X-ray diffraction (WAXD) and polarizing optical microscopy (POM). PEG soft segment in the polyurethane was found
to be crystalline at room temperature. However, when the temperature was raised to PEG’s melting point, polyurethane did not
melt into the liquid state as in the case of pure PEG but changed to an amorphous solid state. In HB-PUPCM, PEG’s molecules
probably are tied to the hard segment chain so strongly by the chemical bonds that they cannot change to a liquid state but
change to the amorphous state in the transition processing. 相似文献