Effect of Far-infrared Radiation on Thermal Cationic Polymerization of Epoxy Resin

Abstract

The effect of far-infrared radiation on cationic polymerization of epoxy resin was studied by thermal quantitative analysis. We use titanium oxide and aluminium oxide as ceramics for low temperature radiation. The absorption spectrum of epoxy resin depicts far infrared absorption from 6.6 to 16 μm. The radiation intensity spectrum of these ceramics were measured using black body standard. Radiation intensity absorbed by epoxy resin was much higher at aluminium oxide than titanium oxide. We performed cationic polymerization of epoxy resin and monitored thermal input and output by differential scanning calorimetry (DSC) using a ceramics coated DSC aluminium pan. Reaction initiation and termination temperatures of polymerization were nearly the same with or without ceramics. The reaction rate was maximal with aluminium oxide, however. We also tested polymerization of epoxy resin after mixing with 1% w/v of ceramics. The relative proportions of aluminium oxide and titanium oxide were varied. DSC measurements showed that the reaction energy of polymerization decreased after addition of ceramic. The decline was more pronounced with increasing aluminum oxide concentrations. For practical application of far-infrared radiation to epoxy resin polymerization, we studied LED encapsulation.