Abstract
The novel phenolic resins with phosphaphenanthrene unit were synthesized by the reaction of a phenolic resin and benzyl alcohol derivative formed by the addition reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with alkoxy benzaldehyde. The epoxy cured resin with phosphaphenanthrene modified phenolic resin was found to provide excellent flame retardancy and high heat resistance, which were required for the advanced printed circuit board applications. In this paper, we report the synthesis, properties, and effect of phosphaphenanthrene-content.
