(80b) Composite Resins for Military Applications

The choice of resin in composite applications is sometimes dictated by legacy choices or by a lack of time and resources to properly choose the best resin for a given application. Composite resins with a wide range of mechanical properties: elongations ranging from 5-300%, strengths ranging from 1-110 MPa, and moduli ranging from 10-3000 MPa, were evaluated for their potential in future composite applications. The neat resins were characterized by dynamic mechanical analysis (DMA) and by flexural, fracture, and impact testing. Fracture morphology was also examined using optical and electron microscopy. The glass transition temperatures of the evaluated resins, as measured by DMA, varied from -20 to 160°C. As neat resin properties do not always directly correlate to composite properties, composites were made using S-2 glass fibers. In one such comparison, a high toughness neat epoxy showed lower composite impact resistance than a brittle neat epoxy. Composites were evaluated by flexural, short beam shear, and impact testing. The resulting neat resin/composite data base of properties will enable quicker and better resin selection in future composite applications.