Abstract
The corrosion tests of two kinds of epoxy resins were conducted by immersing them in an alkaline (KOH) solution. One was the resin of low resistant to alkaline cured with an acid anhydride, the other was the resin of high resistant cured with an amine. They were ground and used for recycling as fillers of the both epoxy resins.Variation in the combination of matrix resin (M) and filler (F) was as follows : C1=M cured with acid anhydride (Ac)/F cured with Ac; C2=M cured with Ac/F cured with amine (Am);C3=M cured with Am/F cured with Am; C4=M cured with Am/F cured with Ac. For C1, potassium hydroxide penetrated into interfaces of the fillers exposed on the surface of a specimen and promoted dissolution around the filler. Although the strength decreased due to dissolution of fillers at the surface, no more penetration occurred inside the specimen. For C2, potassium hydroxide penetrated deeply inside the specimen through filler/matrix interfaces. Because of fillers on the surface falling off and inner matrix around fillers dissolving gradually, the strength decreased remarkably. On the other hand, for C3, potassium hydroxide penetrated into the layer close to the surface and the strength decreased.The strength recovered by drying the specimen reversibly. For C4, fillers at the surface dissolved and potassium hydroxide penetrated deeply inside through the interfaces.Fillers inside the specimen dissolved gradually. The strength decreased and did not recover by drying it. In general, chemical degradation is thought to be one of important factors for these recycled materials, since they have low resistance to alkaline environment caused by filling ground resins.
