A Novel Thermoplastic Composite for Marine Applications: Comparison of the Effects of Aging on Mechanical Properties and Diffusion Mechanisms

Abstract

This article investigates and compares the effects of hydrothermal aging on carbon fibre / Elium™ thermoplastic composite and on carbon fibre / vinylester thermoset composite for marine application. Accelerated aging tests are performed by immersion in deionised water at 70 °C.Water diffusion, monitored by regular weighing, shows that both composites as well as Elium™ resin exhibit non-Fickian behaviour. Analytical models are proposed to fit the experimental curves and to identify and compare diffusion parameters. The aging effects on the microstructure are evaluated using SEM, while irreversibility of degradation mechanisms is investigated by desiccation tests. Mechanical tensile tests, performed before and after aging, show the slight impact of water on tensile modulus and tensile strengths for both materials. Furthermore, it was found that shear modulus and interlaminar shear strength undergo significant alteration related to irreversible physicochemical degradation of the matrix. Studied materials have shown different diffusion behaviours, but similar mechanical properties evolutions.

Influence of environmental conditioning on mechanical properties of carbon dry fibre preformed thermoplastic matrix composites manufactured via automated placement-resin infusion process

“…The second process was more active when the samples were aged at 60 • C in water leading to voids. Frej et al found fibre/matrix interface weakening and increased void content on CF/Elium® due to leaching phenomena [27]. Similar results were observed in the present case where after one month both weight gain and weight loss due hydrolysis of the binder was observed, however after three month the second phenomena was more prevalent.…”

“…The drastic reduction after three months of immersion can be attributed to the leaching of binder phase and presence of voids in the interply region (Fig. 1c and d) [27]. This results in early damage at the interlaminar region.…”

“…In the present work the samples were aged for one month and three months in deionised water. Various studies indicate that degradation rate is higher in distilled water compared to seawater for polymers and composites in terms of diffusion rate and mechanical properties [26][27][28]. This was the motivation to select deionised water.…”

Influence of hydrothermal conditions on the mechanical properties of hybrid composite pipes

“…Several studies on this subject exist in the literature. 1,[16][17][18] Shao et al (2021), hydrothermally aged glass fiber/polycarbonate and glass fiber/nylon six composite samples in 80°C pure water for 25, 100, 400, 900 and 1600 hours. They investigated the water absorption behavior of the aged samples.…”

Energy absorption in carbon fiber honeycomb structures manufactured using a liquid thermoplastic resin

“…24,31 Recently, a number of studies have been reported in the literature on Elium ® -based composite laminates manufactured using the VARTM technique, and many of these studies focus on the mechanical properties of these novel composites. [31][32][33][34][35][36][37][38][39][40] Several breakthroughs have already been reported in terms of tensile properties, 35 fracture toughness, 42 impact performance, 43 and flexural response, 44 where the fiber-reinforced Elium ® composites have exhibited significantly superior mechanical properties compared to the conventional thermosetting epoxy composites. Similarly, multiple studies have also reported comparable shear strengths in both Elium ® and epoxy composites.…”