VOLATILE-FREE PHENOLIC NETWORKS FOR INFRASTRUCTURE

Phenolic resins are high volume materials widely utilized for many purposes, including structural adhesives, composites, coatings, etc. They are also well known to provide fire resistance in many applications including aerospace. Normally, their curing process involves reagents which produce volatile by-products such as water, formaldehyde, or ammonia. This feature has severely limited processability and their utilization in void-free structural applications. The current research has focused on a catalyzed epoxy-phenolic reaction, utilizing commercially available phenolic resins and liquid epoxies to promote a predominately (50-90% by weight) phenolic network which produces little or no volatiles. Surprisingly, ductile films are produced from 50/50 weight % compositions and toughened 80/20 systems have been prepared with T(sub g) higher than 130 degrees C (about 250 degrees F). The materials appear to have significant potential for adhesives and structural composites, wherein the absence of voids could permit significant new products to be prepared for infrastructure and other applications. The synthesis and characterization of these materials will be described.