Oliveira Michelle Souza, da Luz Fernanda Santos, da Costa Garcia Filho Fabio, Pereira Artur Camposo, de Oliveira Aguiar Vinícius, Lopera Henry Alonso Colorado, Monteiro Sergio Neves
Department of Materials Science, Military Institute of Engineering-IME, Rio de Janeiro 22290-270, Brazil.
Department of Mechanical and Aerospace Engineering, University of California San Diego-UCSD, La Jolla, CA 92093, USA.
Polymers (Basel). 2021 Nov 22;13(22):4037. doi: 10.3390/polym13224037.
Dynamic mechanical analysis (DMA) is one of the most common methods employed to study a material's viscoelastic properties. The effect of thermal aging on plain epoxy and a fique fabric-reinforced epoxy composite was investigated by comparing the mass loss, morphologies, and DMA properties of aged and unaged samples. In fact, thermal aging presents a big challenge for the high-temperature applications of natural fiber composites. In this work, both plain epoxy and fique fabric-reinforced epoxy composite were found to have different molecular mobility. This leads to distinct transition regions, with different changes in intensity caused by external loadings from time-aging. Three exponentially modified Gauss distribution functions (EMGs) were applied to loss factor curves of fique fabric-reinforced epoxy composite and plain epoxy, which allowed identifying three possible mobility ranges. From these results it was proposed that the thermal degradation behavior of natural fibers, especially fique fiber and their composites, might be assessed, based on their structural characteristics and mechanical properties.
动态力学分析(DMA)是研究材料粘弹性特性最常用的方法之一。通过比较老化和未老化样品的质量损失、形态以及DMA特性,研究了热老化对普通环氧树脂和麻纤维织物增强环氧复合材料的影响。事实上,热老化对天然纤维复合材料的高温应用提出了巨大挑战。在这项工作中,发现普通环氧树脂和麻纤维织物增强环氧复合材料都具有不同的分子流动性。这导致了不同的转变区域,随着时间老化,外部载荷会引起强度的不同变化。将三个指数修正高斯分布函数(EMG)应用于麻纤维织物增强环氧复合材料和普通环氧树脂的损耗因子曲线,从而确定了三个可能的流动性范围。基于这些结果,有人提出,可以根据天然纤维,特别是麻纤维及其复合材料的结构特征和力学性能来评估其热降解行为。