Kwiecień Konrad, Kwiecień Arkadiusz, Stryszewska Teresa, Szumera Magdalena, Dudek Marta
Faculty of Materials Science and Ceramics, AGH University of Science and Technology, 30-059 Krakow, Poland.
Faculty of Civil Engineering, Cracow University of Technology, 31-155 Krakow, Poland.
Polymers (Basel). 2020 Nov 28;12(12):2830. doi: 10.3390/polym12122830.
Polyurethane flexible joints (PUFJ) and fiber reinforced polyurethanes (FRPU) have shown great potential in the repair and protection of masonry and concrete structures. However, some questions have been raised about the durability of such solutions. The accelerated weathering and thermal stability tests carried out so far have shown the mechanical stability of PS-polyurethane in temperatures up to 100 °C and some UV-induced surface degradation. The paper reports the results from tensile tests of PS-polyurethane, used in the technologies mentioned above after being subjected to aging in different corrosive factors, a thermal analysis of unaged polymer which consists of DSC-TGA and dilatometry studies, and SEM-microscopy observation of the specimens with the indication of the elemental composition (EDS). PS-polyurethane showed low sensitivity to weathering with exposition to UV-radiation, some reactiveness to aqueous environments of a different chemical nature, and resistivity to soil and freezing in both air and water. SEM observations indicated changes in the composition of mineral fillers as the main effect of immersion in different water solutions. DSC-TGA studies showed the thermal stability of PS-polyurethane up to 200 °C and degradation proceeding in five stages. Dilatometry studies revealed that the first-degree thermal degradation over 200 °C causes a serious loss of mechanical properties.
聚氨酯柔性接头（PUFJ）和纤维增强聚氨酯（FRPU）在砖石和混凝土结构的修复与保护方面展现出了巨大潜力。然而，对于这类解决方案的耐久性也出现了一些问题。迄今为止所进行的加速老化和热稳定性测试表明，聚苯乙烯 - 聚氨酯在高达100°C的温度下具有机械稳定性，但存在一些紫外线引起的表面降解现象。本文报道了聚苯乙烯 - 聚氨酯在不同腐蚀因素下老化后用于上述技术的拉伸试验结果、由差示扫描量热法 - 热重分析法（DSC - TGA）和膨胀计研究组成的未老化聚合物的热分析结果，以及带有元素组成指示（能谱分析，EDS）的试样的扫描电子显微镜（SEM）观察结果。聚苯乙烯 - 聚氨酯在暴露于紫外线辐射时对老化表现出低敏感性，对不同化学性质的水性环境有一定反应性，并且在空气和水中对土壤和冻结具有抗性。扫描电子显微镜观察表明，浸泡在不同水溶液中主要导致矿物填料成分发生变化。差示扫描量热法 - 热重分析法研究表明，聚苯乙烯 - 聚氨酯在高达200°C时具有热稳定性，降解过程分五个阶段进行。膨胀计研究表明，超过200°C的一级热降解会导致严重的机械性能损失。
