INTERFACIAL POLYCONDENSATION OF NYLON-6,6 AT THE GLASS-FIBER SURFACE AND ITS EFFECT ON FIBER-MATRIX ADHESION

The surface of glass fibres was modified using chemical treatments to im prove fibre-matrix interface properties. Interfacial polycondensati on was performed with the fibre acting as the interface, and nylon-6,6 chains were grafted on the free hydroxyl groups located at the fibre surface. Grafted nylon was observed through the scanning electron micr oscope. The effect of the treatment on the fibre-matrix adhesion was i nvestigated by measuring the interfacial shear strength in fragmentati on micromechanical tests. The two-parameter Weibull distribution was u sed to analyse the experimental results. Polarized optical microscopy showed the existence of a transcrystalline layer in treated samples, i ndicating better fibre wettability by the matrix. Scanning electron mi croscopy confirmed the presence of an excellent bonding between fibre- and matrix in treated samples, whereas in untreated samples, fibre pul l-out was predominant, indicating poorer fibre-matrix adhesion.