Abstract
Finishing of glass cloths with methacryl silane formed physisorbed silane which was able to be removed from glass fiber surface by washiag with methanol. The physisorbed silane was found to arise from the oligomerization of silane molecules from the measurement of molecular weight distribution of physisorbed silane by gel permeation chromatography. Such a physisorbed silane was suggested to migrate into vinylester resin in the process of fabrication of glass cloth/resin laminates. In order to examine the effect of physisorbed silane on the mechanical properties and the dynamic viscoelasticity was measured for the laminates and for the resin mixed with oligomeric silane as a model of the interphase component between glass fiber and resin matrix. Glass transition of the laminates and of the resin mixed with the physisorbed silane shifted to higher temperature in proportion to the amount of the physisorbed and the oligomeric silane, respectively. The fracture toughness of resin mixed with oligomeric silane decreased in proportion to the amount of the silane. This result showed that the crosslinking density of the mixture of resin and oligomeric silane increased. In order to confirm such a structural change from molecular viewpoint, the vicinity of glass fibers in resin matrix was measured by microscopic FT-IR. The resulting spectra showed that the physisorbed silane affected the curing of resin near glass fiber. These results suggested that the mechanical properties of the interphase between glass fiber and resin matrix was influenced by the formation of the physisorbed silane.
