Ambient cure POSS–epoxy matrices for marine composites

A room-temperature cure epoxy consisting of diglycidyl ether of bisphenol-F (DGEBF) and diethylene triamine (DETA) was modified with 26.5 wt.% and 63.5 wt.% octaglycidyl polyhedral oligomeric silsesquioxane (POSS) to investigate elevated temperature thermomechanical performance. Composites fabricated using vacuum assist resin transfer molding (VARTM) were compared to vinylester and epoxy standards. POSS modified matrices were low viscosity of 0.25–0.40 Pa s. Although Tg was 20% lower than vinylester, we observed an increase of >300% in 150 °C storage modulus, >50% in tensile modulus, >35% in flexural modulus, and the complete elimination of a heat distortion temperature (HDT) up to 200 °C. The matrices demonstrated an excellent balance of flow, wetting, and pot-life behaviors making them attractive alternatives for ambient cure marine applications.