Improved mechanical properties of positive‐pressure filtered CNT buckypaper reinforced epoxy composites via modified preparation process

In the present study, a positive‐pressure filtration method was proposed to prepare carbon nanotube buckypapers (CNT BPs) with desirable porosity and mechanical properties. The obtained BPs were then infiltrated with epoxy via vacuum‐aided resin transfer molding (VARTM) process without the use of a solvent. Some of the impregnated composites were directly cured under a vacuum pressure. The others were put into a hot‐press to cure under a higher pressure of 0.7 MPa. Results have shown that the tensile strength and modulus of the vacuum cured composites were obtained as 215 MPa and 13.3 GPa, whereas these two values could reach 319 MPa and 20.3 GPa, respectively, for the hot‐press cured composites. The glass transition temperature of the hot‐press cured composites was also improved by 7% compared with that of the vacuum cured composites. Furthermore, SEM observation revealed that the BPs were infiltrated well with epoxy and good interfacial bonding between CNTs and epoxy was obtained. This study has demonstrated that the random aligned CNT BPs reinforced epoxy composites possessing desirable mechanical properties can be fabricated by using conventional processes when the microstructure of the BPs is improved. POLYM. COMPOS., 39:1647–1654, 2018. © 2016 Society of Plastics Engineers