Mechanical and interfacial properties of bare basalt fiber

As an emerging eco-friendly fiber, the continuous basalt fiber (BF) has been widely used to reinforce polymers. However, there is a lack of information on the mechanical and interfacial properties of bare BF, which may be of great importance for the design of high-performance material. In this paper, the chemical constitution and morphology tests, single fiber tensile tests, Zeta potential, and dynamic contact angle measurements were employed to characterize the perspective of BF raw materials formulators and sizings designers. The results revealed that the bare BF surface was smooth in axial direction and homogeneous in radial direction. The tensile strength from single fiber tensile tests depends on the gage lengths. In particular, the biggest tensile strength by arithmetic statistics of 2620 MPa and Weibull statistics of 2669 MPa was achieved at the same gage length of 20 mm. By means of the analysis of mathematical model regression, the corrected tensile modulus of bare BF was 87.72 GPa. With decreasing pH values, the zeta potential of bare BF was −32.22 mV at the neutral solution. The surface energy of bare BF was 67.80 mN/m, and was dominated by its polar component. More importantly, the results demonstrated that the raw materials of basalt should be melted by electrically aided flame furnaces, and cationic or non-ionic reagents should be selected for sizings formulas which was emphasized on chemical or electrical interactions between BF and resins.