Resin Transfer Moldable Phenylethynyl Containing Imide Oligomers

As part of an effort to develop high performance/high temperature materials for composite fabrication via resin transfer molding (RTM) and resin infusion (RI), phenylethynyl-containing imide oligomers (PEIs) have been investigated. Uncured resins with low and stable melt viscosities and when cured, high glass transition temperatures ( T g S) and acceptable mechanical properties, are needed for RTM and RI processes. High performance/high temperature composites from these materials are potentially useful in advanced aerospace vehicles such as reuseable launch vehicles (RLVs). Several PEIs were prepared and evaluated for melt flow behavior and mechanical properties after thermalcuring. Candidate materials exhibited the combination of properties required for RTM with melt viscosities of0.4–1.0 Pa s at 280°C and melt stability for > 2 h at 280°C. Flat, void-free composites fabricated by RTM gave cured T g s as high as 350°C, high mechanical properties, and excellent stability at 288°C. The chemical, physical, and mechanical properties of these resins and their composites are discussed.