Sarcinella Antonella, de Aguiar José Luís Barroso, Frigione Mariaenrica
Department of Innovation Engineering, University of Salento, 73100 Lecce, Italy.
Department of Civil Engineering, University of Minho, 4800-058 Guimaraes, Portugal.
Materials (Basel). 2022 Mar 28;15(7):2497. doi: 10.3390/ma15072497.
Starting from two low-cost, low-environmental-impact polymers belonging to the Polyethylene Glycol (PEG) family, i.e., PEG 800 and PEG 1000, two form-stable phase change materials were produced. The two PEGs differ in molecular weight and, as a consequence, the melting and crystallization range of temperatures. The PCMs were obtained, including the PEG, in a liquid state, inside the pores of Lecce Stone flakes, obtained as waste pieces from its processing. A simple and inexpensive impregnation process was selected to produce the PCMs, thus adopting low-environmental-impact materials and cheap processes, and respecting circular economy principles. The two PCMs, the first composed of PEG 800, namely LS/PEG800, and the second composed of a 50/50%wt. mix of the different LS/PEGs, i.e., LS/PEG800_LS/PEG1000, were added as aggregates to four types of mortars, based on aerial and hydraulic lime, gypsum, and cement. The obtained mortars were characterized in their fresh state to assess their workability, and in a solid state after a proper cure to determine their characteristic Latent Heat Thermal Energy Storage (LHTES) properties and mechanical properties in both flexural and compressive modes, taking the mortars not containing any PCM as the reference. The results revealed that, with the proper selection of mortar formulations, it was possible to achieve suitable workability and adequate mechanical characteristics. The selection of a PEG with a low range of phase change temperatures, such as PEG 800, allows one to obtain mortars characterized by a melting/crystallization range that can be considered appropriate in applications characterized by cold climates. The production of a mixed PCM, composed of both PEGs, led to mortars displaying a large interval of melting/crystallization temperatures, which could be suitable in both warm and cold climates.
从两种低成本、低环境影响的聚乙二醇（PEG）家族聚合物，即PEG 800和PEG 1000出发，制备了两种形状稳定的相变材料。这两种PEG的分子量不同，因此其熔化和结晶温度范围也不同。相变材料是在从其加工过程中获得的废弃碎块的莱切石薄片的孔隙内，以液态形式包含PEG而制得的。选择了一种简单且廉价的浸渍工艺来制备相变材料，从而采用低环境影响的材料和廉价的工艺，并遵循循环经济原则。将两种相变材料，第一种由PEG 800组成，即LS/PEG800，第二种由不同LS/PEG的50/50%重量混合组成，即LS/PEG800_LS/PEG1000，作为骨料添加到基于气硬石灰、水硬石灰、石膏和水泥的四种类型的砂浆中。对所获得的砂浆在其新拌状态下进行表征以评估其工作性，并在适当养护后的固态下确定其特征潜热热能储存（LHTES）性能以及弯曲和压缩模式下的力学性能，以不包含任何相变材料的砂浆作为参考。结果表明，通过适当选择砂浆配方，可以实现合适的工作性和足够的力学特性。选择具有低相变温度范围的PEG，如PEG 800，能够获得在寒冷气候特征的应用中具有可认为合适的熔化/结晶范围的砂浆。由两种PEG组成的混合相变材料的制备导致砂浆呈现出较大的熔化/结晶温度区间，这可能适用于温暖和寒冷气候。
