Progress in materials for marine composite structures

Developments have been made in reinforcements and resins for application in marine composite structures. Advanced Glassfiber Yarns, LLC, has recently commercialized a new glass fiber product called VeTron™ High Performance Glass Roving. The fiber was designed for cost-effectiveness: it has a large diameter; it is produced in a single end roving; and it is sized for vinyl ester. VeTron/vinyl ester laminates fabricated by VARTM outperformed E-glass and S-2 Glass laminates by significant margins including 39 percent higher average compression strength than S-2 and 32 percent higher average tensile modulus than E or S-2 Glass. Resin developments have also been made. Although vinyl esters have cure characteristics suitable to the fabrication of large structures, good mechanical properties, and generally high glass transition temperature (T _g), there are applications in which an epoxy might offer performance benefits over a vinyl ester. Although there are epoxy resins developed for Vacuum Assisted Resin Transfer Molding (VARTM) that result in laminates with excellent properties, they do not have the values of fracture toughness and T_g required for Naval applications. Applied Poleramic, Inc., under Navy funding, recently developed an epoxy resin that has a unique combination of properties including high fracture toughness and T_g. In addition, the resin has a long working life but attains a high degree of cure at room temperature.