Silane-treated glass bead surfaces: Their characterization by atomic forcemicroscopy and their effect on the yield stress of filled poly(vinyl chloride)

The silane-treatment of glass beads, chosen as a model filler, was carried out under various drying and heating conditions and the characterization of the treated layer was carried out, gamma-Aminopropyl methyldiethoxysilane was used as silane, and the amounts of silane treated were varied from 0.5 to 10 times those required for monolayer coverage. The silane-treatment of the beads was carried out using an aqueous solution. The fixing ratio of si lane was estimated by carbon analysis, and was affected by the concentratio n of silane and the treatment conditions, especially by heating. The subseq uent heating of the treated beads at above 100 degrees C was useful in orde r to increase the fixing ratio. The topography of the silane-treated layer was observed using atomic force microscopy. As a result, the observed surfa ces differed, dependent upon the silane concentration, the treatment condit ions and the methanol washing procedure for removing the unfixed silanes fr om their surfaces. The yield stress of poly(vinyl chloride) as a typical ductile matrix filled with the treated beads was then investigated. It was improved by silane-tr eatment, but the unfixed silanes on the bead surfaces adversely affected th e improvement.