The Effects Of Reactive Carbon Nanotubes On Interface Bonding And Mechanical Properties Of Fiber Reinforced Composites

Carbon nanotubes(CNTs) is a kind of new quasi-one-dimensional carbon material. As a result of their unique structure and excellent mechanical, thermal and electrical properties, CNTs have been considered to be ideal reinforcing fillers in composites. However, because of their aggregation and lacking of interfacial adhesion with matrices, there is only marginal improvement or even decrease in mechanical properties of nanocomposites after adding commercial CNTs into polymer matrices. The functionalization of commercial CNTs is one of the best methods which can take full advantage of their performance by improving CNTs dispersion and bonding with polymer matrices.In this paper, a kind of reactive multi-walled CNTs (r-MWNTs) was prepared through amino-functionalization and reacting with the butyl glycidyl ether. And the r-MWNTs were incorporated in an epoxy matrix. Then the epoxy matrix containing r-MWNTs was reinforced by T1000 carbon fibers and PBO fibers. And the multi-scale composites were prepared on a filament winding machine.It was demonstrated that the epoxy with r-MWNTs exhibited much lower surface energy and better wettability than that of pristine epoxy. But there is little influence on viscosity. After adding 1 wt% r-MWNTs, the tensile strength and interlaminate shear strength (ILSS) of NOL-rings demonstrated an enhancement of 14.7% and 27.8%, respectively, compared to the pristine epoxy composites. In addition, scanning electron microscopy (SEM) studies revealed that the addition of r-MWNTs could significantly improve the interfaces bonding between T1000 carbon fiber and epoxy matrix. The dynamic mechanical analysis results also showed that the glass transition temperature of the composites increased from 185.9℃to 201.5℃after the addition of r-MWNTs.For PBO fiber/epoxy composites, after adding 0.5 wt% r-MWNTs, The wettability of the uncured epoxy was evaluated by measuring the surface energy and the contract angle between the fiber and epoxy. It was demonstrated that the epoxy with r-MWNTs exhibited much better wettability than that of pristine epoxy. And there is little influence on viscosity. The tensile strength, tensile modulus, elongation and interlaminate shear strength (ILSS) of r-MWNTs NOL-rings demonstrated an enhancement of 11.0%,1.9%,16.5% and 61.1%, respectively, compared to the pristine epoxy composites..In addition, scanning electron microscopy (SEM) studies revealed that the addition of r-MWNTs could significantly improve the interfaces bonding between PBO fiber and epoxy matrix. The dynamic mechanical analysis results also showed that the glass transition temperature of the composites increased from 128.2℃to 133.5℃after the addition of 0.5 wt% r-MWNTs.