Mechanical Properties of Basalt Fiber Reinforced Composites Prepared by Partial Pyrolysis of a Polymer Precursor

ABSTRACT: Heat resistant composites reinforced with continuous basalt fibers were made by incomplete pyrolysis (to 650–7508C in nitrogen) of their precursors – composites with a polysiloxane matrix. The flexural strength of the unidirectional composites ranges from 620 to 820MPa or from 405 to 510MPa for composites pyrolyzed to 650 or 7508C, respectively. The Young’s and tensile modulus from the resonant frequencies range from 50 to 80 GPa, shear modulus from 10 to 22 GPa. The shear modulus values increase after pyrolysis to 7508C, which expresses the increasing integrity and stiffness of the material. After exposition to hot air (at 650 or 7508C) the strength fell further and the failure mode became brittle