Development and Characterization of a New Epoxy Foam Encapsulant as an Ablefoam Replacement

摘要

A new epoxy foam encapsulant, EF-ARIO/20, has been developed at Sandia National Laboratories (SNL) as a replacement for Ablefoam', an epoxy foam encapsulant used in the W76 Arming, Fusing, and Firing (Al%) system. Since it contained toxic ingredients including a known carcinogen, Ablefoarn' is no longer commercially available. It has been demonstrated by scanning electron microscopy (SEM) that the microstructure of the new epoxy foam is similar to that of Ablefoam. Mechanical properties of tensile and compressive strength, and tensile and compressive modulus, and thermal properties of glass transition temperature TJ, and coefficient of thermal expansion (CTE) have been measured for the new foam. Electrical properties of dielectric constant, dissipation factors, volume resistivity, and dielectric strength were also measured. These property measurements are comparable to those of Ablefoam. Development and characterization of the new foam will be discusse; and a comparison of mechanical, thermal, and electrical properties for the new epoxy foam and Ablefoam will be reported.