This Small Business Innovation Research (SBIR) Phase II project seeks to develop and demonstrate flame-resistant, polymer-composite materials based on novel benzoxazine resin chemistries. In the Phase I project, low-viscosity benzoxazine resins were synthesized and composite formulations prepared that exhibit suitable processing characteristics for use in composite manufacture, as well as good mechanical strength and flame resistance. These successes were achieved through the development of polymer synthesis techniques, and validated by the subsequent fabrication and testing of continuous fiber-reinforced composites. For example, the Phase I results showed that these new polymer formulations offer significantly reduced processing temperatures, which simplifies composite manufacturing processes and reduces tooling costs. In addition, the fiber-reinforced composites produced using these materials exhibited 15-20% higher tensile strengths and 50% higher toughness values as compared to composites fabricated using the as-synthesized (i.e., not toughened) material. This finding is important and shows that composites with strengths comparable to those of epoxy-based systems, but with superior flame resistance, can be achieved with these new materials. <br/><br/>The broader impact/commercial potential of this project will initially be in the electronics and aerospace markets. Flame-resistant polymers and composites are becoming increasingly important systems in both of these industries. In each case, the use of fire-resistant materials offers enhanced public safety, while also improving the overall performance of the systems in which they are used. The value of high-strength flame-resistant materials is perhaps most evident in the civil aviation industry. In this instance, the transition to composite materials offers a significant weight savings, with reductions in weight accounting for a large percentage of recent improvements in aircraft fuel efficiency, while also enhancing the flame resistance of aircraft structures. In addition, the use of advanced materials is expected to increase steadily in electronics applications over the next 10 years, and the further development and commercialization of benzoxazine resins will provide the users of this technology with enhancements in both fire safety and system-level performance.