Abstract: Prepreg composite materials that include a fiber layer and a prepreg resin composed of a bismaleimide resin component, a thermoplastic toughening agent and a resin distribution stabilizer. The bismaleimide component is an amorphous mixture of at least three different bismaleimide monomers and a co-curing agent. The prepreg is useful in panel construction where a honeycomb core is sandwiched between two sheets of composite material.

Abstract: Prepreg composite materials that include a fiber layer and a prepreg resin composed of a bismaleimide resin component, a thermoplastic toughening agent and a resin distribution stabilizer. The bismaleimide component is an amorphous mixture of at least three different bismaleimide monomers and a co-curing agent. The prepreg is useful in panel construction where a honeycomb core is sandwiched between two sheets of composite material.

Abstract: The present invention provides plastic-based fiber-reinforced honeycomb, and a process for its preparation. The fiber-reinforced honeycomb has high temperature durability yet can be fabricated and handled by simple techniques. Honeycomb structures in accordance with this invention have the strength, impact resistance and processing characteristics of thermoplastic materials and yet offer high temperature resistance and solvent resistance characteristics which permit such processing steps as the application of multiple coatings for purposes of density adjustment and enhancement of mechanical properties.

Abstract: This disclosure addresses resin systems which contain thermosetting materials and thermoplastic modifiers, the resin systems being formed by dispersing particles of thermoplastic solids in the thermosetting materials, the particles being soluble in the resins at temperatures below the resin system gelation temperature. According to this disclosure, the systems are improved by the use of a blend of two types of thermoplastic material--a high glass transition temperature thermoplastic such as a poly(benzophenone-imide) and a high toughness thermoplastic such as a poly(ether-imide). By appropriate adjustment of the relative amounts of these two thermoplastics, resin system properties such as toughness, service temperature, thermal stability and solvent resistance can be adjusted to optimum levels.

Abstract: Thermosetting resins for use in high performance fiber-reinforced composites are toughened without compromising their processability by the inclusion of micron-sized particles of thermoplastic material which are solid at ambient temperatures but solubilize in the resins at a temperature below the gel temperature of the thermosetting resin. By appropriate selection of the solubilization temperature (or temperature range) of the thermoplastic material, one achieves a composite product having intralaminar or interlaminar toughness emphasized or a combination of both. The invention is of particular utility when applied to bismaleimide resin systems.

Abstract: Vinyl polybutadiene maleimide prepolymers which are peroxide curable are provided. The prepolymers are formed from the reaction product of a vinyl polybutadiene providing pendant vinyl groups and a maleimide and, more particularly, a mixture of aliphatic maleimides with cycloaliphatic or aromatic maleimides in combination with a peroxide-free radical initiator. The prepolymer is a vinyl polybutadiene backbone structure having grafted maleimide polymers forming cross-linking between polybutadiene backbone segments. The resultant prepolymer can be subsequently cured to a hard resin by heating in the presence of a peroxide-free radical initiator to form cross-linking between vinyl polybutadiene structures through the pendant vinyl groups. The resultant hard resin provides strength retention at elevated temperatures and exhibits a flexibility and strength without being brittle.