"Effect of Nanofiller on the Mechanical Properties of Carbon Fiber/Epoxy Composites under Different Aging Conditions"

The raw materials used in this study were unidirectional carbon fiber fabric (CF, ZFS Materials Co., Ltd., Wuxi, China) and bisphenol-A E51 resin (EP, Nanton Synthetic Materials Co., Ltd., Wuxi, China).The weight of the carbon fiber is 300 g/m2, and the thickness is 0.167 mm. Surface-treated MWCNTs were purchased (Zhongke Nano Materials Co., Ltd., Chengdu,  China), and they were treated with a mixture of sulfuric acid and nitric acid (3:1), which introduced oxidation groups on the CNTs. The MWCNTs were stirred evenly in an  acetone solvent for 2 h to obtain MWCNT acetone dispersion. Then, the MWCNT acetone dispersion was added to an E51 solution to achieve 0.5 wt.% content and sonicated at about 60 Cforanother 2 h under a power of 40 kHz. Surface-treated halloysite nanoclay (Mingchuang Materials Co., Ltd., Xi’an, China) was added to an appropriate amount of epoxy resin to achieve 2 wt.% content under stirring for 2 h at 25 C. Then, the nanoclay-resin mixture was taken out. The resin/nanofiller mixture was infiltrated into CF fabric to prepare a prepreg. The prepreg was placed in the air for 72 h and then dried in a vacuum oven at 60 C for 2.5 h. The unidirectional CFRP laminates were prepared by a molding process at a pressure  of 1.1–1.3 MPa. The thickness of the CFRP laminates is about 2 mm.