Effect of sea water on composite material's properties

• Main Author: Cai, Huiying
• Other Authors: Seah Leong Keey
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/53643
• Institution: Nanyang Technological University

Composites are an emerging field of material that is under intensive research by many researchers, as it possesses exceptional mechanical properties with the most outstanding being their high strength-to-weight ratio. They also offer good corrosion resistance and thus are highly suitable for marine applications. There is growing recognition that utilizing composites in marine applications would help reduce life cycle costs, but their application is limited by the lack of design codes and material databases pertaining to the long-term effect of seawater on composites’ properties. For this project, the effects of hygrothermal degradation on the thermal and mechanical properties of a carbon fibre reinforced polymer (CFRP) are determined through experimental means. The specimens were immersed for prolonged periods of time in artificial seawater at temperatures ranging from -20℃ to 80℃. This temperature range is meant to be reflective of the possible exposure conditions in marine applications, such as drill pipes that stretch from the ocean surface right to the seabed or beyond. The extent of degradation in the specimens will be examined by looking at the weight gain and the change in the glass transition temperature. Composites made from Toray carbon fibres, with a common Derakane Vinyl Ester (VE) resin from the Dow Chemical Company were chosen for the study. For this project, the study is a single factor experiment with temperature as the varying factor and the salinity of the artificial seawater held constant at 3.5%. This project characterized the effects of prolonged immersion in seawater at different temperatures on the composites’ properties and thus provides a general framework for future tests and research. Lastly, it contributed to the material database for use of composites in marine applications, which allows for material reliability and ultimately the design life to be determined with confidence.