Effect of the incorporation of a novel natural inorganic short fiber on the properties of polyurethane composites

Glass fiber reinforced plastics have been used in many structural applications for the last 40 years. Although extensively used, glass fibers are still expensive for many applications that require low cost raw materials. Glass fibers also have high density and leachable components that can reduce specific mechanical properties (property to weight ratios) and performance of composites. In this work, a novel inorganic short fiber (Silexil) obtained from mineral resources was characterized and tested as a reinforcing agent in plastics. This type of fiber was characterized by electron microscopy, water picnometry, Knoop microhardness and infrared spectroscopy. Fibers were also incorporated into polyurethane and the composites obtained were mechanically tested. Results showed that the novel fiber has a composition close to 100% pure SiO2 and bulk density (1.73 g/cm3) lower than the density of commercial e-glass fibers (2.65 g/cm3). The novel short fibers are 200-600 μm long and have diameters measuring 10 μm. They have also microhardness values comparable to commercial glass fibers and adjustable by changing the temperature of heat treatment. Mechanical properties of the composites showed that the novel fiber is able to reinforce polyurethane. The advantages of this type of fiber when compared to commercial glass fibers would then be: production of low cost composites with lower densities and comparable mechanical properties.