ABSTRACT
The utmost practical importance of polymer composites materials is due to the modification, and usually improvement, of the properties of the pure polymer. The improvement of mechanical properties, although very different in nature according to the application
of interest and the polymer used, is generally termed as the reinforcement effect [1,2]. This effect includes phenomena such as the increase of the tensile strength and maximum elongation of elastomers, the reduction of brittleness and improvement of fracture toughness, or better abrasion resistance for car tires [3,4]. In general, mechanical reinforcement has been defined as all mechanisms that introduce energy dissipation or storage [5]. Other goals are specific barrier or optical properties, or simply to lower the production costs, which is a nonnegligible factor given the industrial tonnage of composites.
