Preparation And Application Of Three Dimensional Reinforcements With Carbon Nanotubes Grown On The Fiber Surfaces In Situ

Fiber-reinforced composites are increasingly used as structural materials in the aerospace and the wind power industry. The composites with compounded fibers with carbon nanotubes (CNTs) grown in-situ are expected to have high performance and good electrical conductivity. The main purpose of this paper is focused on the growth of CNTs on the surfaces of carbon fibers (CFs) and quartz fiber clothes (QFCs) with different morphologies by chemical vapor deposition (CVD) method, and the three dimensional reinforcements modified epoxy composites with improved interface adhesion, interlaminar shear strength and electrical conductivity. The major work is as following:1. We grew CNTs on CFs surfaces by CVD method and studied the influence of the kinds of catalyst, the concentration of carbon source and catalyst, the growth temperature and time. When the catalyst was Ni(NO3)2 and Co(NO3)2, the resulting products were CNTs. When the catalyst was NiSO4, the resulting products were CNCs. While 0.1 mol/L Co(NO3)2 was used as the catalyst and the flow ratio of C2H2/Ar was 1/10, the diameter of the produced CNTs was small with uniform distribution and a low level of impurity at 650℃. As the extension of the reaction time, CNTs can be uniformly grown on CFs surfaces.2. The uniform growth of different morphologies of CNTs on the QFCs surfaces was realized by CVD method. The results showed that the growth of CNTs was aligned and the CNTs were multiwalled nanotubes with better crystallinity as the QFCs vertically placed at the catalyst concentration of 0.1 mol/L and growth temperature of 650℃. As the extension of the reaction time, the content of CNTs grown on QFCs surfaces increased. The pull-out test showed that the incorporation of CNTs improves interface properties between QF and epoxy matrix. When the growth time of CNTs was 60 min, the interfacial shear strength of QF-CNTs/epoxy system increased by 12% compared to that of QF/epoxy system, and corresponding reinforcing mechanism model was proposed.3. The QFCs-CNTs three dimensional reinforcements modified epoxy composites were prepared by VATRM technique. The FESEM images of the fractured samples showed that aligned CNTs still distributed over the QFCs surfaces, and the CNTs improved the bonding of QFCs and epoxy matrix. Compared to the QFCs modified epoxy composites, the interlaminar shear strength of QFCs-CNTs three dimensional reinforcements modified epoxy composites enhanced by 16.5%. When the growth time of CNTs extended from 3 min to 60 min, the in-plane and out-of-plane electrical conductivity of QFCs-CNTs three dimensional reinforcements modified epoxy composites increased by two orders of magnitude and three orders of magnitude respectively.