Pavlovic Ana, Valzania Lorenzo, Minak Giangiacomo
Department of Industrial Engineering, University of Bologna; Via Luciano Montaspro, 97, 47121 Forlì, Italy.
Polymers (Basel). 2025 Jul 21;17(14):1996. doi: 10.3390/polym17141996.
This review critically examines the effects of moisture absorption on the mechanical and fatigue properties of natural fiber composites (NFCs), with a focus on tensile strength, elastic modulus, and long-term durability. Moisture uptake can cause reductions in tensile strength of up to 40% and in elastic modulus by 20-30% depending on fiber type, mass fraction (typically in the range of 30-60%), and surface treatments. The review highlights Ithat while surface modifications (e.g., alkaline and silane treatments) significantly mitigate moisture-induced degradation, their effectiveness is highly sensitive to the processing conditions. Additionally, hybridization strategies and optimized fiber orientations show promise in enhancing fatigue resistance under humid environments. Despite substantial progress, major challenges remain, including the lack of standardized testing protocols and the limited understanding of multiscale aging mechanisms. Future research directions include developing predictive models that couple moisture diffusion and mechanical deterioration, implementing advanced in situ monitoring of damage evolution, and exploring novel bio-based treatments. By addressing these gaps, NFCs can become more reliable and widely adopted as sustainable alternatives in structural applications.
本综述批判性地研究了吸湿对天然纤维复合材料（NFC）力学性能和疲劳性能的影响，重点关注拉伸强度、弹性模量和长期耐久性。吸湿会导致拉伸强度降低高达40%，弹性模量降低20%-30%，具体取决于纤维类型、质量分数（通常在30%-60%范围内）和表面处理。该综述强调，虽然表面改性（如碱处理和硅烷处理）能显著减轻吸湿引起的降解，但其有效性对加工条件高度敏感。此外，混杂策略和优化的纤维取向在提高潮湿环境下的抗疲劳性方面显示出前景。尽管取得了重大进展，但仍存在重大挑战，包括缺乏标准化测试协议以及对多尺度老化机制的理解有限。未来的研究方向包括开发将水分扩散与机械劣化相结合的预测模型、实施先进的损伤演化原位监测以及探索新型生物基处理方法。通过填补这些空白，NFC作为结构应用中的可持续替代品可以变得更加可靠并得到更广泛的应用。
