Effect of crosslink density of acrylic-epoxy thermoset systems on their physical and mechanical properties

Crosslink density, expressed as XLD, greatly affects physical and mechanical properties of cured film. Crosslink density is influenced by many factors, such as curing temperature, curing time, the ratio of crosslinking agent to main resin, amount of functional groups, type of catalyst, amount of catalyst, resin type and the type of crosslinking agent.In the present work two carboxyl functional acrylic resins and an epoxy resin were used as thermoset resins and crosslinking agent, respectively. Their films were immersed in xylene and by considering of their dimensional changes, crosslink density is calculated according to Flory-Rehner equation. The effect of changes in amount of functional groups and crosslinking density on impact resistance, cupping, and hardness tests was also investigated. Results demonstrated that crosslink density increased by increasing in crosslinker content till carboxyl /epoxide ratio 1:1.Optimum hardness, flexibility and impact resistance of epoxy cured acrylic resin were also obtained at carboxyl /epoxide ratio 1:1. Decreasing in acid value of acrylic resin caused weaker mechanical properties but both acrylic resins with different crosslinking agent content exhibited similar trend in increasing or decreasing of their films features.

کلیدواژه ها:

Acrylic/Epoxy resin ، Crosslink density ، Physical and mechanical properties