Performance of toughened acrylic thermoplastic composites under mode I loading

• Main Author: Ng, Ronald Zi Foong
• Other Authors: Leong Kah Fai
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/167087
• Institution: Nanyang Technological University

The development of advanced material systems, such as composites, has gained popularity due to their remarkable mechanical features, including excellent strength and stiffness relative to weight. While composites are made up of a combination of two materials, a matrix system and reinforcement, advancements in polymer research have led to the development of Elium®, an innovative thermoplastic acrylic resin that cures at room temperature. However, there has been no significant research on the impact of additives on the fracture toughness characteristics of Elium®-based composites with thermoplastic fibres. This final year project aims to explore and investigate the compatibility of Clearstrength® XT100 and Nanostrength® with Elium® resin reinforced with two different thermoplastic fibres – Polyester and Ultra-High Molecular Weight Polypropylene (UHMWPP). The manufacturing of the composites will be achieved using the vacuum assisted resin infusion (VARI) process, and the composites will undergo fracture toughness tests under Mode I loading conditions in accordance with ASTM D5528-13 standards. Analysis of the results revealed that the use of Innegra™/Elium® 1% XT100 and Innegra™/Elium® 2.5% XT100 composites resulted in an increase of 20.74% and a decrease of 22.19% respectively when compared to Innegra™/Elium® composites. However, the Diolen®/Elium® 1% XT100 and Diolen®/Elium® 2.5% XT100 composites exhibited higher fracture toughness values with 5.58% and 50.95% improvement respectively. The rise in fracture toughness is contributed by the rougher de-bonding surface due to the integration of Clearstrength® powder into the Elium® matrix, thereby signifying a toughened Elium® matrix, while the drop could be attributed to manufacturing challenges faced, resulting in the fabrication of a poorer composite. Additionally, both Innegra™/NSElium® and Diolen®/NSElium® composites demonstrated a reduction in fracture toughness by 51.71% and 74.11% respectively when compared to their base counterparts as a result of weak interfacial bonding between the matrix and fibres. The results from this final year project hopes to shed light on possible improvements which may be undertaken to optimize the results, and the possibility of incorporating higher weight percentages of Clearstrength® XT100 to further enhance the outcomes.