Experimental study on mechanical properties of carbon nanotubes/epoxy composites

• Main Author: Lau, Sze Hui.
• Other Authors: Dong Zhili
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Materials::Nanostructured materials
• Online Access: http://hdl.handle.net/10356/48814
• Institution: Nanyang Technological University

In this study, the mechanical properties of epoxy composites with multi-walled carbon nanotubes was studied. Taking neat epoxy sample as reference, the comparison of the mechanical strengthening effects was made at different nanofillers’ content (0.01wt%, 0.05wt%, 0.1wt5, 0.3wt%, 0.5wt%, and 1wt%). Dispersing and mixing procedures were revised to attain better dispersion of MWCNTs in epoxy matrix. The rotational time, rotational speed, and MWCNTs incorporation sequence was found to have influenced the strengthening effect significantly. Effort was also put in to remove the voids beneath the specimens by pre-heating the MWCNTs/epoxy mixture before adding hardener. The mechanical properties measured were the tensile strength and Young’s modulus. The results revealed that the strengthening effect of MWCNTs is more pronounced at low MWCNTs weight percentage. At 0.01wt% of MWCNTs, the tensile strength was ~12.2% higher than pure epoxy sample, whereas the Young’s modulus showed an increment of ~22.3%. However, it was noted that the strengthening effects begin to retard with higher infusion amount of MWCNTs. The fracture surface of MWCNTs/epoxy specimens were studied by scanning electron microscope. From the fracture morphology of the composites, MWCNTs clusters and voids were observed. The dispersion quality was not as good as expected. The fracture mechanism of specimens was due to the de-bonding of MWCNTs from matrix as a result of the weak interfacial bonding. However, the superiority of MWCNTs over other carbon fillers in terms of mechanical properties can be achieved with better dispersion technique in the near future.