EFFECTS OF SURFACE TREATMENTS AND SILICA SIZE ON MECHANICAL PROPERTIES OF SILICA-REINFORCED ELASTOMERIC COMPOSITES

The effect of surface treatments with atmospheric pressure flame plasma (APFP) and epoxy silane (ES) was studied experimentally to improve the mechanical properties of silica-(volume 40% and mean diameters of 2.2, 12.4, 26.6, and 110 gm) reinforced elastomeric composites. The tensile strength (TS) of the composites increased significantly with decreasing mean diameter. When the diameter was 2.2 pm, the TS of the composite was approximately 1.4 times higher than that of the matrix (2.52 MPa). In addition, the TS of the silica-reinforced composites treated with APFP and ES was increased by 8.8 to 13.3% and 9.9 to 12.5%, respectively, compared with that of the matrix. A larger particle size generally resulted in better surface treatment effects. When the diameter was 26.6 pm, the tensile modulus (TM) of the composite was increased approximately twofold compared with the matrix (0.88 MPa), and the TM of the silica-reinforced composites treated with APFP and ES was increased by 15.6 to 22.8% and 21.1 to 25.8%, respectively, compared with the matrix. Therefore, the importance of surface treatments increases with increasing filler particle size. A conventional silane-coupling agent treatment has few disadvantages, such as the use of organic solvents. Nevertheless, the APFP treatment is a fast, economic, and eco-friendly method for improving the mechanical properties.