Dow Epoxy (Midland, Mich.) has developed the COMPAXX 900 foam core system, designed to enable fabrication of wind blades that exceed 40m/131 ft in length. The foam’s small cell size — up to 100 times smaller than cells in chemical-blown foam such as PVC — limits the amount of resin that can fill cut cells at the surface. Other features include good skin-to-core bonding and fatigue resistance, as well as better static performance than PVC foam. Also new from Dow is the VORAFORCE TW series of epoxy systems for fabricating composite pressure vessels to store compressed natural gas (CNG) and liquefied petroleum gas (LPG). The epoxy is said to enable improved impact resistance, dynamic fatigue and low-temperature performance.