Azidosilane polymer—filler coupling agent

This new coupling agent shows promise for use in reinforcing hydrocarbon type polymers, such as polyolefins and polystyrene, with glass fibers and inexpensive mineral fillers. Sulfonyl azide derivatives readily form durable bonds to many thermoplastics at normal extrusion and molding temperatures, without the use of peroxide or sulfur‐type curing agents. Alkoxy silanes, attached to the sulfonyl azide, hydrolyze in the known manner forming bonds to inorganic fillers. Using commercial compounding and injection molding procedures, 40 wt percent of mineral fillers containing 1 percentofan azidosilane coupling agent were incorporated in polypropylene. Very substantial improvements in tensile, flexural and heat distortion properties were obtained with little loss in impact strength. An initial evaluation in a filled polystyrene showed significant, but less dramatic, improvements.