Cure kinetics and viscosity modelling of a high-performance epoxy resin film

The cure kinetics and rheology of an amine-cured TGMDA resin film, M18-1 (Hexcel, France), has been characterised in order to predict the viscosity behaviour under resin film infusion (RFI) process conditions. The kinetic and rheological parameters were experimentally determined using DSC analysis and rheometry. An autocatalytic model was applied to describe the rate of cure accounting for diffusion controlled kinetics at the final cure stage. Further, a chemo-rheological resin model was employed to effectively predict the resin viscosity under non-isothermal and stepped cure cycle conditions, as applied in the RFI process. A preliminary analysis on the effect of fast curing methods on the resin viscosity suggests improved impregnation properties with high temperature ramp rates

Out-of-autoclave cure cycle study of a resin film infusion process using in situ process monitoring

Liquid resin infusion (LRI) of textile tailored reinforcements (TRs) is increasingly applied in new processing technologies for manufacturing carbon fibre composites. This work presents a cure cycle study of an out-of-autoclave toughened resin film infusion (RFI) process as part of the examination of an alternative manufacturing process for composites. To successfully produce laminates using resin film infusion in combination with a fast-curing process, the flow behaviour of the selected resin material under changed processing conditions was investigated. The effect of processing parameters, specifically heating rates and dwell times, on resin viscosity and laminate infiltration was evaluated through experimental work and supported by in situ process monitoring. A DC-resistance sensor system was applied to track the change in resin viscosity during cure. Results showed that cure cycles with a relatively short dwell time and higher heating rate compared to an autoclave cure led to enhanced flow properties of the toughened resin system. High quality laminates, comparable to autoclave panels, were manufactured with vacuum pressure only by modifying the original vacuum bagging arrangement

New surface treatments for low cost carbon fiber

The development of low cost carbon fiber offers the opportunity to rethink strategies for sizing and surface treatments. This paper has focused on developing new chemical treatments for fibers to promote fiber matrix adhesion and improved translation of fiber properties to laminate properties in composite materials. This paper will describe one successful route involving the cyclisation of a reactive nitrene species onto the highly electron rich graphitic surface of carbon fibers. Treated fibers were characterised using X-ray photoelectron spectroscopy (XPS), surface energy analysis (SEA), as well as Atomic Force Microscopy (AFM). Analysis was performed on fibers that had been electrolytically oxidised, sized as well as fibers that were not exposed to any treatments (unoxidised)