Transfer molding imide resins based on 2,3,3′,4′‐biphenyltetracarboxylic dianhydride

Abstract

AbstractPhenylethynyl containing imide oligomers have been under investigation as part of an effort to develop resins for non‐autoclave composite fabrication processes such as resin transfer molding (RTM). These high performance/high temperature composites are potentially useful on advanced aerospace vehicles such as reusable launch vehicles (RLVs). New phenylethynyl terminated imide oligomers (PETI) based upon 2,3,3′,4′‐biphenyltetracarboxylic dianhydride (a‐BPDA) were prepared and characterized primarily by rheological behavior and cured glass transition temperature (Tg). In comparison to resins from the symmetrical isomer (3,3′,4,4′‐biphenyltetracarboxylic dianhydride, s‐BPDA), a‐BPDA afforded corresponding resins with lower melt viscosities and upon curing, higher Tgs. Several resins exhibited an attractive combination of properties such as low and stable melt viscosities required for RTM composite fabrication, high cured Tgs, and moderate toughness. One resin (P10) was used to fabricate flat, void free laminates by RTM. The laminates exhibited high mechanical properties at temperatures to 288°C. The chemistry and physical properties of these new PETIs and the laminate properties of one composition are discussed.