Effect of Matrix Toughening on the Mechanical Properties of Glass Fibre Reinforced Composite

Abstract

Changes in morphology and mechanical properties of glass fibre reinforced composites fabricated using a polyvinylbutyral (PVB) modified phenolic resol resin were studied. The PVB modified phenolic resin systems possessed discrete spheres of PVB evenly dispersed in a phenolic resin matrix at low thermoplastic content. However, at higher concentrations, phase inversion resulted, and the morphology consisted of discrete spheres of phenolic resin embedded in a PVB matrix. The mechanical properties of neat resin films showed maximum values with PVB content of 66.7 phr. But the tensile and flexural properties of the glass fibre composite showed the highest values with PVB 25-42.9 phr, lower PVB levels than those of neat resin films. The tensile and flexural moduli were significantly improved and showed maxima at about 25-42.9 phr, unlike the neat resin films which showed a continuous decrease. The reason is that the interfacial bond between fibre and matrix plays an important role and has been altered by the addition of the PVB to the glass fibre reinforced composite. The composite with increased PVB content showed increased toughness and a smaller damaged area after a drop-weight impact test.