The objective of this program is twofold: to develop adhesives that are (1) processable, high temperature stable, and (2) low cure shrinkage. The formation of polymers form smaller monomers is usually accompanied by a reduction in volume of the final polymer network. This shrinkage creates internal strain and defects in the resin, adversely affecting the mechanical and durability of the polyme and adhesive bond. In Phase I, we have shown that the incorporation of a comonomer that can undergo ring opening during cure can compensate for such shrinkage. In Phase II, we propose to build upon and transition the results to adhesively bonded structures. Current structural adhesives require high bonding temperature and pressure, adversely affecting the manufacturability and reliability of the bonded joints. Based on our prior work, we propose to develop processable, thermooxidative stable adhesives by the synthesis and blending of imide oligomers with defined chain length, chain conformation and chemical composition. The capability of the candidate adhesives developed in this Phase II will be demonstrated by measuring the bond strengths at various test temperatures. We anticipate that the adhesives developed under this program will satisfy the demands of Air Force aerospace structures, as well as provide a dual-use capability for micro- and opto-electronic applications
