Corrosion Behavior of Unsaturated Polyester Resins with Different Crosslink Density

Abstract

The effect of crosslink density of unsaturated polyester resin on the corrosion resistance was investigated. Cured unsaturated polyesters with different crosslink density were immersed in pure water and potassium hydroxide solution. Since the weight of resin increased in proportion to the square root of immersion time in pure water, the diffusion coefficient of water into the polymer was calculated by using the Fick's Law. The greater the crosslink density, the smaller the diffusion coefficient was. On the other hand, corrosion layers with uniform thickness were observed on the specimen surfaces immersed in potassium hydroxide solution. The corrosion depth increased in proportion to the immersion time. The slope between the corrosion depth and immersion time was defined as corrosion rate. The corrosion rate increased with increasing in the crosslink density.