A Comparative Analysis on the Processing Aspects of Basalt and Glass Fibers Reinforced Composites

In the current scientific scenario, basalt fibers (BF) have been proposed as an alternative to synthetic reinforcements of polymeric resins due to their relatively low cost, good mechanical characteristics and reduced environmental impact. In this context, the aim of this work has been to analyze the effect of basalt fibers on the processing behaviour of a commercial polypropylene resin (PP) and to compare their performances to glass fibers (GF), which are commonly used as synthetic reinforcement of polymers. GF/PP and BF/PP composites containing varying wt% of reinforcement (GF or BF) were prepared by melt blending and characterized via thermal conductivity tests, thermogravimetric analysis, differential scanning calorimetry, capillary and rotational rheology, and scanning electron microscopy (SEM) to gain information on the heat transfer ability, thermal stability, melting and crystallization parameters, flow properties and morphology. The obtained results showed similar performance of basalt and glass fibers in many aspects. More specifically, an improvement of thermal conduction was always observed when increasing the amount of the reinforcement in the composite material. A higher thermal stability was confirmed in almost all compounds. The addition of fibers did not lead to alterations in the melting point or in the degree of cristallinity of the PP. At the typical process shear rate, the real viscosity of the composites remained unchanged and similar to that of the neat matrix, even at the highest fibers loading. Both glass and basalt fibers appeared homogeneously dispersed in the matrix as supported by SEM and oscillatory dynamic tests.