Preparation and performance of heat released 2PZ-PS-co-MAA microcapsule-type latent curing agent

A heat released microcapsule-type latent curing agent was successfully prepared by solvent evaporation technique with 2-phenylimidazole (2PZ) as the core material and styrene/methacrylic acid copolymer (PS-co-MAA) as the wall material. The chemical structure, core material content, surface morphology, size distribution and curing characteristics of this microcapsule-type curing agent were characterized by Fourier transform infrared spectrum(FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), granulometer and differential scanning calorimetry (DSC). The obtained microcapsules have a smooth surface and display a narrow size distribution with the mean size about 15.60 μm, and its wall thickness is about 0.5 μm with core material content about 39.19%. In addition, the one-component adhesive made from the microcapsules and epoxy resin E-51 shows advanced curing characteristics and latent properties. It is found that the E-51/PS-co-MAA microcapsule system can be cured at 100°C in 30 min and its shelf life at room temperature is more than 32 days.