Co-authors​ :

 Hamza TARIN (FRANCE), Jamal FAJOUI (FRANCE), Julie COCAUD , Frederic JACQUEMIN (FRANCE), Sylvain FRÉOUR , Amandine CELINO  

This study investigates the role of diffusion kinetics in epoxy resin, which is vital for understanding its behavior under extreme environmental conditions while ensuring its applicability for industrial purposes, particularly in marine applications, chemical processing plants, oil and gas transport, and the aerospace industry. Our methodological approach included a detailed experimental analysis of epoxy resin samples, focusing on their behavior under wet-aging cycles under controlled climatic conditions. The key to our approach was the use of absorption-desorption cycles under extreme environmental conditions (70°C and 85%R.H. for the absorption cycle and 70°C and 7%R.H for the desorption cycle) to study the diffusive response of the material. The material was subjected to two cycles each of absorption and desorption. The sequence for the second cycle was repeated to allow the observation and understanding of the response of the material to alternating environmental conditions. Extensive gravimetric measurements for several months allowed us to precisely predict the water content of the material during these phases. The results revealed a complex interaction between the polymer matrix and water. Notably, the study discovered the presence of a dual-phase diffusion showcasing a non-Fickian behavior, and later transitioning into a Fickian behavior, indicative of the material’s adaptive response to moisture conditions. In addition, a Finite Element Analysis (FEA) simulation was performed using ABAQUS to validate our experimental findings and provide deeper insight into the diffusion process.
A recurrent challenge for the composite manufacturing industry is to regulate the water absorption capacities of materials subjected to challenging environmental conditions, particularly for high-pressure applications where minimal moisture absorption is critical. Our findings have far-reaching implications and provide a full understanding of the response of epoxy resins to moisture, which is critical for enhancing the reliability and dependability of composites under harsh conditions. It emphasizes the need to continuously innovate manufacturing processes, with the goal of minimizing water intake while retaining the integrity and performance of the material. Our research not only clarifies the complicated dynamics of moisture interaction inside polymer matrices, but also sets the way for future research in the manufacturing of more robust and efficient composites for industrial purposes.