Performances Recovery of Flax Fiber Reinforced Composites after Salt-Fog Aging Test

Abstract

In the present paper, the performance recovery under conditions of discontinuous exposure to a marine environment of a natural fiber-reinforced composite (NFRC) reinforced by flax fibers was assessed. In particular, this laminate was initially exposed to salt-fog for 15 and 30 days, and then stored in a controlled air condition for up to 21 days. The flax fiber-reinforced composite showed coupled reversible and irreversible aging phenomena during the wet stage, as well as evidencing a significant mechanical recovery during the dry stage. Unlike the stiffness, the laminate showed a noticeable recovery of its flexural strength. This behavior affected the composite material toughness. A simplified approach was applied to define a topological map of the material toughness at varying drying times. The results highlight that the composite shows maximum toughness at intermediate drying times thanks to the strength recovery, in addition to its residual plasticity. This approach allows us to better determine that the strength is more closely related to reversible degradation phenomena, whereas the stiffness is mainly correlated to irreversible ones, implying relevant effects on the toughness of the composite exposed to a wet/dry cycle.

Investigation of Zalacca Midrib – Based Composites Fibers as Prosthetic Socket Materials Accounting for a Variety of Alkali and Microcrystalline Cellulose Treatment.

“…Subsequently, alkali treatment treatment resulted in the formation of a more stable and compact cellulose II structure compared to cellulose I [24]. A similar increase in fiber density due to alkaline treatment was observed in flax fiber [25], borassus fiber [26], and cantala fiber increased by ± 30% [27]. Alkaline treatment of kenaf fiber can increase fiber density and decrease fiber volume because fiber diameter was reduced due to the loss of amorphous and other impurities in fiber.…”

Flax–Glass Fiber Reinforced Hybrid Composites Exposed to a Salt-Fog/Dry Cycle: A Simplified Approach to Predict Their Performance Recovery

“…For instance, a possible reversible phenomenon consists in the adsorption of water in the bulk of the composite constituents (that exhibit an elastoplastic mechanical behavior in the composite laminate [18]). This absorbed water can be removed thanks to its natural evaporation during the dry phase [42]; 2. Irreversible aging region.…”