Ex-situ Liquid-molding And Toughened Carbon Composite

Resin transfer molding (RTM) has drawn more attention in the last decade because its manufacture cost is significantly lower than traditional techniques of fabricating fiber-reinforced composites. However, the major limitation of composites via RTM in the aerospace industry is their lower impact damage resistance compared to those via traditional methods.National Key Laboratory of Advanced Composites(LAC) in Beijing Institute of Aeronautics Materials(BIAM) has developed a new medium temperature curing epoxy resin system ,of which the glass transition temperature is 119.88℃, for resin transfer molding(RTM). In order to investigate the relation between viscosity and time-temperature, The rheological behavior of the system was studied by DSC and viscosity experiments. A rheological model based on the dual-Arrhenius equation was established and used to simulate the rheological behavior of the resin, which was in good agreement with experimental data. The processing window of the resin system can be well determined by the developed model. The rheological model is important for processing simulation and quality control of RTM processing for high performance composites.Due to the RTM's major limitation - low impact damage resistance, this thesis concentrates on toughening epoxy resin for RTM technology by a new concept "Ex-situ". It showed that 73% increasing of toughness in modified composites was achieved without the reduction of other mechanical properties. SEM has showed the periodically interleaved system where the co-continuously connected granular structure occurs layer by layer between each ply and the interlayer was relatively very thin.