is paper describes a study in which EPDM-based rubber composites were investigated aiming at developing formulations subjected to restrictions on cost and the properties of the material. e contents of components other than calcium carbonate, para nic oil, and CBS vulcanising accelerator, as well as additives and processing conditions, were kept constant. Fractional factorial design coupled with computational numerical optimisation was used to minimise the number of mixtures. e results demonstrate that statistical design of experiments and particle swarm optimisation (PSO) algorithms are promising methods to design composition variables. Mixture costs as low as 1.92 US$/kg can be achieved in compositions containing, for example, 107 phr of calcium carbonate, 95 phr of para nic oil, and 1.13 phr of CBS accelerator. e corresponding composite propertypredicted values were 66.8 Shore A for hardness, tensile strength of 7.8 MPa, 570.8% elongation at break, and 23.0% rebound resilience. is demonstrates that, in this way, the desired product with speci ed characteristics can be comfortably manufactured at minimum cost.

In industrial practice involving mixtures of raw materials, it is desirable to be able to predict how a change in their proportions will affect the product's properties. In this work the effect of three major vulcanized rubber raw materials was investigated. All other raw materials, as well as processing conditions, were kept constant. Ten formulations were vulcanized by compression moulding (175 8C, $17 MPa, during 5 minutes) and characterized. The statistically valid property equations calculated from the characterization results show that a range of compositions exists within which the final product has the desired properties and can still be comfortably manufactured.