Benzoxazine Resins for Composite Materials: Recent Developments

摘要

Fiber reinforced composite materials continuously gained importance for aerospace applications since the 1950’s. Epoxy-based formulations have long history since established for applications in primary structures of military aircrafts and subsequently in large commercial aircrafts. Ongoing development trends of composite materials have been improved toughness, durability, and increased hot/wet glass transition temperature (Tg). Despite considerable efforts, with epoxy chemistry a hot/wet Tg of about 160°C could not be exceeded, which limits the service temperature of the respective parts to about 100 – 110°C. At the same time, highly crosslinked systems showing high Tg are particularly difficult to toughen. Alternative resin systems with superior hot/wet Tg like BMI resins had been developed, but combining high temperature performance with excellent toughness turned out to be impossible to achieve with these resin chemistries.