Study of Curing Reaction Kinetics and Dynamic Mechanical Property on nm-SiO2/Epoxy Used As the Matrix of Fiber Reinforced Composite Applied to the Repair and Local Reinforcement of Oil and Gas Pipelines

Abstract

In-field repair of a damaged pipeline and crack arrester on a high pressure pipeline must be performed safely, efficiently, rapidly and reliably. Recent developments in high property para-aramid fiber and carbon fiber reinforced composite repair and local reinforcement have led to their increased usage across aviation and space engineering. The disadvantage of epoxy used as the matrix of the fibers is that the interfacial bond between fiber and matrix is poor. In the research, SiO2 nanoparticles were used to modify the matrix, and when the content nm-SiO2 is 0%, 3% and 6% (mass fraction), the curing reaction kinetics were analyzed by Ozawa and Kissinger methods respectively through Differential Scanning Calorimetry (DSC) tests at various heating rate of 10°C, 15°C and 20°C; Dynamic mechanical properties were analyzed through Dynamic Mechanical Analysis (DMA) tests. The result shows: (1) Characteristic temperature of curing reaction has a close relation with heating rate. The curing reaction peaks of the system move towards high temperature region with the increase of heating rate, and the temperatures at peak initiation and peak finish have similar phenomenon. (2) The reaction order is 0.87 in nm-SiO2/epoxy system, which is similar to that in unmodified epoxy system. The curing reaction of all the systems are complex reaction process. The activation energy in nm-SiO2/epoxy system is a little decreased by about 3%. (3) The addition of nm-SiO2 infused in epoxies can make the storage modulus of composite increased, especially the storage modulus of nanocomposite containing 3wt% nm-SiO2 improved obviously. The addition of nm- SiO2 in epoxy can make rigidity and resistance to deformation of material improved.