Oun Amer, Manalo Allan, Alajarmeh Omar, Abousnina Rajab, Gerdes Andreas
Centre for Future Materials, Faculty of Health, Engineering and Sciences, University of Southern Queensland, Toowoomba 4350, Australia.
KIT Innovation Hub, Department of Civil Engineering, Geo and Environmental Sciences, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
Polymers (Basel). 2022 Apr 29;14(9):1841. doi: 10.3390/polym14091841.
Natural fibers are now becoming widely adopted as reinforcements for polymer matrices to produce biodegradable and renewable composites. These natural composites have mechanical properties acceptable for use in many industrial and structural applications under ambient temperatures. However, there is still limited understanding regarding the mechanical performance of natural fiber composites when exposed to in-service elevated temperatures. Moreover, nanoparticle additives are widely utilized in reinforced composites as they can enhance mechanical, thermal, and physical performance. Therefore, this research extensively investigates the interlaminar shear strength (ILSS) and flexural properties of flax fiber composites with graphene at different weight percentages (0%, 0.5%, 1%, and 1.5%) and exposed to in-service elevated temperatures (20, 40, 60, 80, and 100 °C). Mechanical tests were conducted followed by microscopic observations to analyze the interphase between the flax fibers and epoxy resin. The results showed that a significant improvement in flexural strength, modulus, and interlaminar shear strength of the composites was achieved by adding 0.5% of graphene. Increasing the graphene to 1.0% and 1.5% gradually decreased the enhancement in the flexural and ILSS strength. SEM observations showed that voids caused by filler agglomeration were increasingly formed in the natural fiber reinforced composites with the increase in graphene addition.
天然纤维如今正被广泛用作聚合物基体的增强材料，以生产可生物降解和可再生的复合材料。这些天然复合材料在环境温度下具有可用于许多工业和结构应用的机械性能。然而，对于天然纤维复合材料在实际使用的高温环境下的机械性能，人们的了解仍然有限。此外，纳米颗粒添加剂在增强复合材料中被广泛使用，因为它们可以提高机械、热学和物理性能。因此，本研究广泛调查了不同重量百分比（0%、0.5%、1%和1.5%）的石墨烯增强亚麻纤维复合材料在实际使用的高温环境（20、40、60、80和100°C）下的层间剪切强度（ILSS）和弯曲性能。进行了力学测试，随后进行微观观察，以分析亚麻纤维与环氧树脂之间的界面相。结果表明，添加0.5%的石墨烯可使复合材料的弯曲强度、模量和层间剪切强度得到显著提高。将石墨烯含量增加到1.0%和1.5%会逐渐降低弯曲强度和层间剪切强度的增强效果。扫描电子显微镜（SEM）观察表明，随着石墨烯添加量的增加，天然纤维增强复合材料中由填料团聚导致的孔隙越来越多。
