Study Of Cyanate Ester Modified By Carbon Nanotubes

MWNTs were purified by strong acid, these functionalized MWNTs were characterized by Fourier transform infrared spectrum(FT-IR),Transmission electron microscopy(TEM),X-Ray diffraction(XRD) .The result indicated that acidification of MWNTs can get ride of impurity and cut MWNTs into small size.Moreover, hydroxyl group, carboxyl and carbonyl group were grafted on the MWNTs.Because of cyanate ester's brittleness, we selected MWNTs to toughen it, prepared the MWNTs/DGEBA/BADCy composites. Differential scanning calorimetry (DSC) ,gelation time test and FT-IR were employed to study the reactivity of BADCy modified by MWNTs .The effection of MWNTs on the composites' structure and property were also studied. TEM and scanning electronic microscopy (SEM) were used to watch composites' microstructure.The quasi-static mechanical properties, dynamic mechanical analysis (DMA) and Thermogravimetric analysis (TGA) of composites were investigated. The toughening mechanism of BADCy modified by MWNTs has been proposed.The results showed that MWNTs could disperse well in the resin, the less content of MWNTs, the better dispersion in the composites.The impact strength and the flexural strength of the composites can be respectively improved about 15% and 8%, when MWNTs were 1wt%.Compared with DGEBA / BADCy system, the storage modulus and loss modulus of the composites increased, and the composites' glass transition temperature was 30℃ higher than its with 1.5wt% content of MWNTs.The composites based on high modulus carbon fiber and Bisphenol A Dicyanate ester which modified by MWNTs were manufactured in this paper. The mechanical properties including hot-wet of the composites have also been tested.The microstructure of the fracture of the composites has been analyzed using SEM .The toughing mechanism has also been proposed.The results showed that the addition of MWNTs intensively improved the composite's thermal stability and mechanical properties. It was found that, when 1wt% MWNTs were introduced, the shear strength can be improved about 31%; and when 1.5wt% MWNTs were introduced, the flexural strength can be improved about 23%. The composites toughened by MWNTs showed excellent properties, which could be used as main force-bearing components of areospace.