Effects of CTBN rubber on mechanical properties and morphology of bisphenol epoxy resins

Abstract

In this research, the effect of CTBN rubber on epoxy resin had been investigated. Two types of resins (Epon 828 and Epon 862) and three kinds of hardeners are Jeffamine T-403, Imicure EMI-24 and DCA221 used for found optimum ratio between resin and hardener. From results, epoxy resin without CTBN rubber had the high mechanical properties. The best mechanical properties were obtained at 100 to 80 wt% for Epon 828/Jeffamine T-403 and 100 to 40 wt% for Epon 862/Jeffamine T-403. These formulae gave the high mechanical properties. After that, the various concentrations of the CTBN rubber that added to epoxy resin were prepared. Addition of small amount CTBN rubber led to the decrease of mechanical properties of the materials. This was due to the phase separation between epoxy resin phase and CTBN rubber phase. In contrast, when high amount of CTBN rubber was added to epoxy resin, the mechanical properties increased. This may be due to the increase of particle size of CTBN rubber in epoxy resin. Scanning Electron Microscope was used to study the phase separation between epoxy resin with hardener and CTBN rubber. The phase separation of CTBN rubber in epoxy resin with hardener matrix was observed. It can be concluded that CTBN rubber was less compatible with epoxy resin with hardener.