Effectiveness of 3-Aminopropyl-Triethoxy-Silane as a Coupling Agent for Phosphate Glass Fiber-Reinforced Poly(caprolactone)-based Composites for Fracture Fixation Devices

Abstract

Silane (3-Aminopropyl-triethoxy-silane) solutions with differing concentrations (0—10 wt%) were prepared from an aqueous ethanol solution (90% ethanol + 10% deionized water, by volume). Phosphate glass fibers were immersed in these silane solutions for time periods between 15 and 120 min. It was found that the silane treatment yielded fiber mass gains and it was noted that shorter immersion times resulted in higher mass additions. The largest gain in mass was observed for 10 wt% silane treatment and 15 min immersion time, with the fibers gaining 4.1 wt%. Subsequent XPS confirmed the presence of silane at the surface of the fibers. Poly(caprolactone)-based unidirectional composites were made by compression molding. The tensile and the bending properties of the silane composites improved significantly. Composites made with fibers treated with 10 wt% silane had 47% higher tensile strength and 86% higher tensile modulus than those of the untreated fiber-based composite control specimens. The bending properties also proved superior to the control composite (52% higher bending strength and 79% higher bending modulus). Degradation tests of the composites were carried out in deionised water at 37°C and found that silane-based composites retained higher tensile and bending properties than their untreated counterparts.