Miscibility and influence on each other of a UV photo-initiated thermosetting polymer blend of radical and cationic systems

Thermoset blends engage an interest into polymer materials using photopolymerization. Our work is inscribed within a project which consists to control the degree of crosslinking in three dimensions during UV photo-curing. Two different reaction mechanisms were considered to enlarge the control of properties. The goal of this thesis was to check the miscibility between two thermosetting polymers using radical and cationic chemical mechanisms. Then their influence on each other was studied by thermal analysis. The experimental system was Bisphenol A propoxylate diacrylate for the radical curing and 3,4-epoxycyclohexylmethyl 3,4-cyclohexanecarboxylate for the cationic. They were initiated by 2-hydroxy-2-methylpropiophenone and Triarylsulfonium hexafluoroantimonate salts mixed respectively. Several polymer blends were manufactured and influence of weight proportions and process temperature were studied. As a result, high thermal stability and properties were determined and homogeneity of these materials was verified by Thermogravimetric Analysis. Differential Scanning Calorimetry showed that thermal properties of blended materials didn’t follow any linear blending law. It was also noticed that the temperature needs to be highly considered. The cationic resin, which used to be post-cured to reach a high degree of curing, was highly cured at 80°C. But the radical network, which used to crosslink very fast at ambient temperature, didn’t fully cure. We concluded that some interactions occur between the two systems but the presence of Interpenetrating Polymer Networks was not confirmed