An unsaturated polyester resin (AROPOL FS3992, Ashland) with a styrene content of 42% (w/w), was used as polymer binder. The polymerisation process of the resin system was activated by cobalt octoate (0.5 phr), as promoter, and 50% methyl ethyl ketone peroxide solution (2 phr), as initiator. Physical and mechanical properties of cured resin are shown in Table 1.