Thermoset polymers chemo-rheology dedicated to reactive rotational moulding (RRM) understanding and control

This study comes within the scope of New Technology for Energy, particularly for high pressure hydrogen storage. Reactive Rotational Moulding has been identified as an adapted process for hydrogen-tight liners manufacturing. Thus the Reactive Rotational Moulding process has been studied in order to find theoretical tools dedicated to the understanding of such a reactive forming process. Chemical kinetics of four polyurethanes and poly-epoxides reactive systems have been determined on classical isothermal conditions and original aniso-thermal conditions i.e. on temperature ramps. Aniso-thermal conditions have been selected because they corresponds better to real process conditions. Rheological behaviour have also been characterized on two different approaches, an isothermal one and on temperature ramps. In particular, viscosity have been described as a function of heating rate. These physical and chemical results have been compiled in an original state diagram in order to show material properties evolution in a time-temperature space. The whole ex situ characterizations are then managed to described the behavior of the different formulations during the rotational moulding. Moreover they allow to form specific materials and so to widen the range of material to thermoset polymers. Finally, in order to correlate theoretical deduction to real reactive systems evolution, the elaboration of innovating monitoring tool based on ultrasonic analysis has been studied. To begin, polymerization monitoring criteria have been identified and then specific techniques have been set to monitor these criteria in real forming process. (author)