Possible use of gypsum waste from ceramics industry as semi-reinforcing filler in epoxidized natural rubber composites

In recent years, the incorrect disposal of industrial solid wastes is one of the main reasons for serious environmental pollution. The appropriate recycle of these waste materials in commercial purpose is the key way to protect the environment. In the present study, the suitability of gypsum waste (GW) from ceramics factory as a filler in epoxidized natural rubber (ENR) was explored. Most importantly, the properties of ENR/GW composites were compared with those of ENR composites filled with most widely used non-reinforcing filler calcium carbonate (CaCO3). In both ENR/GW and ENR/CaCO3 composites, the values of torque difference, hardness and tensile modulus increased steadily with increasing filler content. However, at same filler loading level, the mechanical and dynamic mechanical properties of ENR/GW composites were better as compared to those of ENR/CaCO3 composites. ENR/GW composite also exhibited considerably higher thermal stability as compared to either unfilled ENR or ENR/CaCO3 composite. As a whole, GW could be used as a cost-effective semi-reinforcing filler in ENR composites.