About the influence of temperature and environmental relative humidity on the longitudinal and transverse mechanical properties of elementary alfa fibers

Abstract

Composites reinforced with plant‐based fibers present a high potential for valorization in new industrial applications due to their good specific mechanical characteristics, renewability, and recyclability. In order to accelerate their wide industry adoption, it is critical to assess their behavior and durability in heat and humid environments. This article aims at investigating the effects of temperature and relative humidity (RH) on the longitudinal and transverse mechanical properties of the lignocellulosic fibers extracted from alfa plant (Stipa tenacissima L). For this purpose, tensile and nanoindentation tests were performed on elementary alfa fibers subjected to a thermal cycle of 200°C. The fibers were held at various periods of 15, 30, 60 and 120 min. The test results showed that the longitudinal and transverse Young's moduli are moderately affected by short thermal cycles having duration of 15–30 min. However, for longer thermal cycle (i.e., 2 hr), a degradation of 21% for the transverse modulus was recorded. This degradation doubled for the longitudinal modulus (43 vs. 21%). A similar trend was observed for the breaking strength. This study also showed that the RH strongly affects the mechanical performances of alfa fibers.

Hierarchical thermoplastic biocomposites reinforced with flax fibres modified by xyloglucan and cellulose nanocrystals

“…Natural fibres have many advantages compared to synthetic fibres, such as their renewability, biodegradability, wide availability and low cost associated with low density and high specific mechanical properties. However, the implementation of these materials in industrial applications is limited by the low thermal and dimensional stability of natural fibres, especially in humid conditions, as well as poor interfacial adhesion with several polymer matrices Garat, Le Moigne, Corn, Beaugrand, & Bergeret, 2020;Khaldi, Bouziane, Vivet, & Bougherara, 2019;Le Duigou, Bourmaud, Balnois, Davies, & Baley, 2012;Le Duigou et al, 2017). The fibre / matrix interface plays a key role in stress transfer within biocomposite materials and their resulting mechanical performance.…”