Details
Material hierarchy: Polymer - Thermoset
Of the allylic family, diallyl phthalate (DAP) is the most commonly used molding material. A relatively high-priced, premium material, DAP has excellent dimensional stability and a high insulation resistance (5 × 106 megohms), which is retained to an extremely high degree after exposure to moisture (e.g., the same value is retained after 30 days at 100% relative humidity and 80°F).
Both DAP and DAIP (diallyl isophthalate) compounds are available, the latter providing primarily improved heat resistance (maximum continuous-service temperatures of 350-450°F vs. 300-350°F for DAP). Compounds are available with a variety of reinforcements (e.g., glass, acrylic, and polyester fibers). The physical and mechanical properties are good, and the materials are resistant to acids, alkalis, and solvents.
DAP compounds are available as electrically conductive and magnetic molding grades, achieved by incorporating either carbon black or precious metal flake.
Most DAP compounds are used in electrical/electronic (they can withstand vapor-phase soldering temperatures), aircraft, and aerospace applications. Prepregs are used to manufacture composite parts.