Durability study of vinylester/silicate nanocomposites for civil engineering applications

The durability of fiber-reinforced polymer (FRP) composite materials in humid and harsh environments is an important consideration for acceptance of these materials in civil engineering applications. Reducing the moisture ingress may improve the durability of FRPs. The addition of modified inorganic powder, such as silicate nanoparticles, may improve several important properties of polymers, such as barrier properties, fire retardancy, dimensional stability and mechanical strength. The present work aims to evaluate the effect(s) of the addition of silicate nanoparticles on the durability-related properties of vinylester polymer used as matrix for FRPs in civil engineering applications. To conduct this preliminary study, nanocomposites containing 5% organo-modified or untreated silicate were characterized by using X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The diffusivity of moisture was measured by immersing samples in a 50 degrees C water bath. Barrier properties were determined by measuring the maximum water uptake, water absorption rate and coefficient of diffusion. Aging was performed by complete immersion of nanocomposites samples in a NaOH solution at 50 degrees C. Scanning Electron Microscopy (SEM), tensile tests and Fourier Transform Infrared spectroscopy (FTIR) analyses were performed before and after conditioning to evaluate the matrix degradation. Experimental results show that the use of organo-silicate leads to an improvement of barrier properties characterized by a decrease of the coefficient of diffusion. It also increases mechanical properties and leads to a significant decrease of chemical degradation. (C) 2015 Elsevier Ltd. All rights reserved.

纤维增强聚合物（FRP）复合材料在潮湿和恶劣环境中的耐久性是土木工程应用中接受这些材料的一个重要考虑因素。减少水分侵入可能会提高FRP的耐久性。添加改性无机粉末，如硅酸盐纳米粒子，可能会改善聚合物的几个重要性能，如阻隔性能、阻燃性、尺寸稳定性和机械强度。本研究旨在评估添加硅酸盐纳米粒子对土木工程应用中用作FRP基体的乙烯基酯聚合物耐久性相关性能的影响。为了进行这项初步研究，通过X射线衍射（XRD）和透射电子显微镜（TEM）对含有5%有机改性或未处理硅酸盐的纳米复合材料进行了表征。通过将样品浸泡在50℃的水浴中来测量水分扩散率。通过测量最大吸水量、吸水速率和扩散系数来确定阻隔性能。通过将纳米复合材料样品完全浸泡在50℃的NaOH溶液中进行老化。在处理前后进行扫描电子显微镜（SEM）、拉伸试验和傅里叶变换红外光谱（FTIR）分析，以评估基体降解情况。实验结果表明，使用有机硅酸盐可改善阻隔性能，其特征是扩散系数降低。它还提高了机械性能，并导致化学降解显著降低。© 2015爱思唯尔有限公司。保留所有权利。