Preparation and characterization of epoxy composites containing well–dispersed nanoclay

• Main Author: Ang, Sharmin Xin Hui
• Other Authors: Lu Xuehong
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Materials
• Online Access: http://hdl.handle.net/10356/76732
• Institution: Nanyang Technological University

Epoxy – based composites with carbon fibre reinforcement are increasingly used as structural materials in load bearing applications as it can yield high performances including high strength and stiffness, dimensional and thermal stability and high corrosion resistance. However, there are limitations in improving composite properties incorporated with conventional fillers that has almost reached its saturation point as improving properties generally involve compromises. For example, stiffness is often traded for toughness and toughness is traded for young’s modulus, tensile strength and glass transition temperature. To solve the compromise issues on epoxy, the specific aim of this project is to develop a new method to toughened epoxy-based composites while retaining their good mechanical and thermal properties. A new toughening method was introduced to toughen epoxy at a low loading ratio by using new nanoclay modifier containing compatible and reactive groups to epoxy matrix. With the new modifier, the modified nanoclay exhibited better dispersibility in epoxy. Subsequently, a series of epoxy composites filled with nanoclay with varied surface properties were fabricated and tested to systematically investigate the effect of nanoclay chemistry onto the properties of the composite. It was found that the POSS – modified clay has significantly increased dispersion and exfoliation in the epoxy resin as compared to the commercial clay (I.30E) that was modified by organic surfactant. Owing to the excellent dispersion, the POSS-modified nanoclay showed remarkable effectiveness in toughening epoxy even at a low loading ratio of less than 1%. More importantly, the high tensile strength and high glass transition temperature of epoxy can be retained with the use of the POSS-modified nanoclay. Finally, it was found a lower polarity of the surface of the modified nanoclay yielded a higher compatibility with the epoxy matrix, due to the closer match in chemistry between the modified nanoclay and the epoxy matrix.