Effect of basalt fiber optimal length/number/coupling agent on the properties of rubber composites

Abstract The influence of different types of short fibers, fiber content, and coupling agents on the properties of short fiber‐reinforced rubber‐based composite materials was studied. The results of physical and mechanical property tests showed that the optimal combination was a fiber length of 9 mm, fiber content of 3 phr, and coupling agent KH560. Contact angle tests revealed that under the same conditions of fiber length, the addition of an adhesive significantly increased the contact angle with water compared to the BF powder without adhesive modification, indicating a significant improvement in the surface hydrophobicity of BF after adding the adhesive. The surface pretreatment of BF was significantly improved, with KH560 and sodium stearate showing the best wetting properties. XPS tests indicated that BF9 treated with sodium stearate exhibited higher tensile strength and overall performance compared to untreated BF9, and it had the highest comprehensive performance among BF9 treated with KH550, KH560, and Si69. EDS results showed that more coupling agents were attached to the surface of fibers treated with both KH560 and KH550, resulting in stronger adhesion to the rubber matrix. Surface tension results indicated that sodium stearate provided the best uniform coating on BF in this experiment. Fourier transform infrared spectroscopy (FTIR) results indicated the grafting of functional groups such as methyl (CH ₃ ) onto BF after the secondary modification. Highlights BF9 treated with C ₁₇ H ₃₅ COONa had the highest comprehensive performance. Grafting of functional groups (CH ₃ ) were onto BF after the secondary modification. Sodium stearate provided the best uniform coating on BF. The optimal experimental combination was length9 mm, 3 phr, coupling agent KH560. Adhesive increased the contact angle with water compared to that of untreated.