Accelerated Aging of Natural Fiber Composites (NFCs), Their Fabrication Methods, Industrial Applications, Challenges, and Future Directions: An Overview

The long-term durability of natural fiber composites (NFCs) remains a critical challenge, particularly in structural applications exposed to outdoor environments. Due to their chemical composition and hydrophilic nature, natural fibers are highly susceptible to moisture, heat, and ultraviolet (UV) rays. These environmental factors accelerate degradation, compromising the structural integrity of NFCs over time. Hence, ensuring their durability is essential for their use in high-performance industrial applications. Despite these challenges, NFCs have attracted growing interest in recent decades as potential alternatives to conventional composites or construction materials. This interest is driven by several technical advantages such as natural fibers are lightweight, widely available, environmental-friendly, and offer specific mechanical properties comparable to those of synthetic fibers (glass fibers). Common plant-based natural fibers used in composites include flax, hemp, jute, kenaf, sisal, abaca, ramie, coir, PALF (pineapple leaf fiber), bamboo, date palm, oil palm, etc. This review paper provides a brief overview of NFCs and their fabrication methods. It then explores the effect of accelerated aging on their mechanical performance under hygrothermal and weathering conditions. Additionally, the paper highlights various industrial applications of NFCs across multiple sectors, identifies key challenges, and offers suggestions and future directions for the development and industrial adoption of NFCs.

天然纤维复合材料（natural fiber composites, NFCs）的长期耐久性始终是一项关键挑战，在暴露于户外环境的结构应用中尤为突出。由于其化学组成与亲水特性，天然纤维极易受到水分、热量以及紫外线（ultraviolet, UV）的侵蚀。这些环境因素会加速材料降解，长期下来会损害天然纤维复合材料的结构完整性。因此，保障其耐久性对于其在高性能工业领域的应用至关重要。尽管存在上述挑战，近几十年来天然纤维复合材料作为传统复合材料或建筑材料的潜在替代品，受到了越来越多的关注。这种关注度的提升源于其多项技术优势：天然纤维质量轻盈、来源广泛、环保友好，且具备可与合成纤维中的玻璃纤维（glass fibers）相媲美的特定力学性能。复合材料中常用的植物基天然纤维包括亚麻（flax）、大麻（hemp）、黄麻（jute）、洋麻（kenaf）、剑麻（sisal）、马尼拉麻（abaca）、苎麻（ramie）、椰子壳纤维（coir）、菠萝叶纤维（pineapple leaf fiber, PALF）、竹子（bamboo）、海枣（date palm）、油棕（oil palm）等。本综述论文对天然纤维复合材料及其制备方法进行了简要概述，随后探讨了湿热与风化条件下加速老化对其力学性能的影响。此外，本文还阐述了天然纤维复合材料在多个行业的多样化工业应用，明确了其面临的关键挑战，并为天然纤维复合材料的研发与产业化应用提供了建议与未来发展方向。