|
Latent catalyst curing system of epoxy resin/anhydride had been used for many years in commerce. However, there was still a lot of research spaces in this field. We focused on the curing mechanism of the latent catalyst (Chromium (Ⅲ) acetylacetonate) of epoxy resin/anhydride system in this research.
DSC in this research was used to proceed curing thermal analysis of the samples, and to analyze the Tg of the cured products. Oil bath was used to test the pot life of the samples in isothermal condition. FT-IR was used to proceed isothermal dynamic experiments with different carrier (KBr or PE film), and to study the change with time of the samples in isothermal condition. For proceeding the isothermal dynamic experiments more convenient with FT-IR, a heating accessory was designed by ourselves.
In this research, di-carboxyl group or di-hydroxyl group cocatalysts were added to reduce the exothermic reaction cause of microgel in later stage, and to reach the goal of reducing the time of post cure. This research also studied the effect of curing agents, concentration of latent catalyst, heating rate, di-carboxyl group or di-hydroxyl group cocatalysts, and cocatalyst of different molecular weight in this curing system. Then, we also find the gel time and Tg of the experiment samples.
Furthermore, we found that KBr has the capability to accelerate curing reaction during dynamic experiments. So the PE film was used as a carrier to replace KBr to proceed experiments, and a DSC experiment was designed for this phenomenon. Then Al2O3, which is stable, was added to compare with KBr and PE film. According to the result, heat transfers maybe the major factor to this phenomenon.
|