Low-Cost and High-Impact Environmental Solutions for Military Composite Structures

The EPA recently enacted new emission standards for composite manufacturing and repair that specifically target styrene as a regulated hazardous air pollutant HAP. In this report, the Army Research Laboratory team developed two resin systems that contain considerably less styrene but similar viscosities as compared to commercial vinyl ester resin systems. The FAVE neat resins and composites have slightly inferior strength, modulus, and thermal properties, but superior fracture toughness as a result of the plasticizing effect of the long fatty acid chains that replace all but 10 to 20 wt of the styrene. The BM-VE neat resin and composites have similar strength, modulus, and thermal properties, but also superior fracture toughness as a result of the bimodal molecular weight distribution of VE monomers with styrene contents as low as 30 wt. Both low VOCHAP resins produce far less emissions than commercial resin systems and can be used as drop-in replacements for existing vinyl ester technologies in the composites industry.