Investigation on Mechanical Properties and Fatigue Life of Multi-Wall Nanotubes/Graphene Nanoplates/ Benzoxazine/Epoxy Carbon Fiber Laminated Composites

• Main Authors: Lin, Hsiu Ling, 林秀臨
• Other Authors: Yip, Ming Chuen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/33s829

碩士 === 國立清華大學 === 動力機械工程學系 === 103 === The purpose of this research is to adopt mixture of Benzoxazine and epoxy resin as matrix and mixture of multi-wall nanotubes and graphene Nanoplates as nano-reinforcement through modification between Benzoxazine and epoxy resin and utilizing nano-reinforcements, to improve the mechanical properties and fatigue life of composite. The study investigates: (1)The influence of Benzoxazine content of resin on mechanical properties; (2)The impact of reinforcing effect and concentration when adopting nanotubes or graphene Nanoplates individually as reinforcement; (3)The best ratio of the mixture of nanotubes and graphene Nanoplates; (4)The influence of concentration of reinforcements in best proportion on mechanical strength and fatigue life of laminated composites. The experimental results show that addition of Benzoxazine can greatly improve tensile and flexural properties, but the material would become hard and brittle with drop of impact strength at the same time. Nanotubes or graphene have beneficial efficiency on materials, because they both can occur micro crack deviation and increase energy to failure. However, when the concentration of nano-reinforcement exceeds certain concentration, the aggregation phenomenon should incur stress concentration, thus the mechanical properties will decrease. According to the experimental result of mixing nano-reinforcement, the 9:1 mixing ratio of nanotubes and graphene Nanoplates is the best ratio for enhancing the mechanical properties. The reinforcements in best ratio added to the laminated composites show good enhancement, improving the tensile strength by 22.28%, the flexural strength by 9.64%, the impact strength by 33.75% and the torsion fatigue life by about three times in contrast with those of neat resin laminated composites. The properties are improved, because the nano-reinforcements enhance the interfaces between matrix and fibers, thus the load can be effectively transferred to fibers. This mechanism is confirmed by observing SEM images of failure surface.