Abstract
In this study, Multi-walled carbon nanotube(MWCNT) was modified with different methods. The Allyl-MWCNTs were prepared via free radical reaction with allylamine, which contains the ethylene groups for increase interaction between MWCNTs and vinyl ester (VE). The TEVOS was grafted on the MWCNTs surface to prepare MWCNT-TEVOS. From the mechanical properties study, the tensile strength of glass fiber/vinyl ester was increased from 227.5MPa to 254.06MPa when 1phr P-MWCNT content was added to neat GF/VE composite. The tensile strength of GF/VE composites was increased to 258.55 MPa (with 1phr TEVOS-MWCNT) and to 275.45MPa (with 1phr Allyl-MWCNT). Modified MWCNT can improve the tensile strength of the GF/VE than that was added with unmodified MWCNT. The fracture toughness (GIC) of GF/VE composites was increased from 0.76 kJ/m2 (neat GF/VE) to 0.83kJ/m2 (with 0.25 phr MWCNT) and to 0.94 kJ/m2 (with 1.0phr TEVOS-MWCNT) and to 1.07 kJ/m2 (with 1.0phr Allyl-MWCNT). Allyl-MWCNT possesses the best interface bonding between fiber and matrix that exhibits best fracture toughness of these three kinds of composites. The Tg of GF/VE composite was 89.05℃. The GF/VE composite with 1phr TEVOS-MWCNT and Allyl-MWCNT shows the Tg which was 107.70℃, and 109.70℃ respectively. It indicated that thermal stability of composite can be improved even when a small quantity of functionalized MWCNTs was added From the mechanical properties study, the tensile strength of carbon fiber/vinyl ester was increased from 369.45MPa to 448.68MPa when 1phr P-MWCNT content was added to neat CF/VE composite. The tensile strength of CF/VE composites increased to 465.15MPa (with 1phr TEVOS-MWCNT) and to 476.45MPa (with 1phr Allyl-MWCNT). Modified MWCNT can improve the tensile strength of the CF/VE than that of unmodified MWCNT/CF/VE composite. The GO/CF/VE composites show the best tensile strength, which were 505.04MPa with 1 phr filler content. The flexural strength of CF/VE composites was increased from 272.45MPa (neat GF/VE) to 501.53 MPa (with 1.0 phr MWCNT) and to 511.45MPa (with 1.0phr TEVOS-MWCNT) and to 521.56MPa (with 0.5phr Allyl-MWCNT).Allyl-MWCNT/CF/VE composite possesses better flexural strength than that of unmodified MWCNT/CF/VE. The GO/CF/VE composites show the best flexural strength, which was 558.07MPa with 1 phr filler content. The fracture toughness (GIC) of CF/VE composites increased from 0.80 kJ/m2 (neat CF/VE) to 0.95kJ/m2 (with 0.5 phr MWCNT) and to 1.04 kJ/m2 (with 1.0phr TEVOS-MWCNT) and to 1.07 kJ/m2 (with 1.0phr Allyl-MWCNT). Allyl-MWCNT/CF/VE exhibits the best fracture toughness due to the improvement of interface bonding between fiber and matrix. The Tg of CF/VE composite was 98.18℃. The CF/VE composite with 1phr TEVOS-MWCNT and Allyl-MWCNT shows the Tg which was 115.67℃, and 116.67℃respectively. It indicated that thermal stability of composite can be improved even when a small quantity of functionalized MWCNTs was added.