Additive Manufacturing of High-Performance Polymers for Extreme Environments.

Additive manufacturing (AM) of high-performance polymers (HPPs) has gained significant research interest due to its potential for applications in extreme environments, including aerospace, automotive, marine, and defense sectors. Components in these applications are often subjected to prolonged exposure to high temperatures, high mechanical loads, and chemically aggressive environments. HPPs are well-suited to such demanding conditions because of their high mechanical properties, thermal stability, flame resistance, and chemical durability. However, the inherent molecular and structural characteristics that provide these properties also pose notable challenges during AM of HPPs. In particular, the effective processing and fabrication of HPPs using AM techniques are limited by their rigid molecular structure, high melting temperatures and viscosities, and complex crystallization behavior. This review focuses on the processing and utilization of HPPs using commercially available AM techniques. Particular emphasis is placed on the relationships among polymer chemistry, rheology, thermal history, crystallinity, process-induced defects, and mechanical performance. Recent applications of additively manufactured HPPs are critically evaluated. The review also compares qualification requirements, environmental durability, and technology readiness with those of conventionally manufactured components. Finally, unresolved challenges and future research priorities are identified to enable reliable, scalable, and certification-ready additively manufactured HPP components for extreme-service environments.