Abstract: Systems and methods of curing a thermoset composite (TSC) to a target state of cure (SOC) are disclosed herein. The methods include heating the thermoset composite to greater than a threshold temperature. During the heating, the methods further include monitoring an actual temperature of the thermoset composite, determining a maximum temperature achieved by the thermoset composite, and determining an elapsed time that the actual temperature of the thermoset composite is greater than the threshold temperature. The methods further include ceasing the heating based, at least in part, on the maximum temperature of the TSC and the elapsed time. The systems include a heating assembly, a support mandrel, a thermoset composite, a temperature detector, and a controller programmed to perform the methods.

Abstract: Methods of co-bonding a first thermoset composite (TSC) and a second TSC to define a cured composite part are disclosed herein. The methods include partially curing the first TSC to a target state of cure (SOC) to define a first partially cured TSC. The partially curing is based, at least in part, on a maximum temperature of the first TSC during the partially curing and on an elapsed time that an actual temperature of the first TSC is greater than a threshold temperature. The methods further include combining the first partially cured TSC with the second TSC to define a partially cured TSC assembly and heating the partially cured TSC assembly to bond the first partially cured TSC to the second TSC, cure the partially cured TSC assembly, and produce a cured composite part.

Abstract: A prepreg comprising a layer of impregnated reinforcing fibers comprising at least one layer of reinforcing fibers impregnated by a resin composition comprising at least a thermosetting resin, a curing agent and an accelerator, such that the accelerator has a gradient concentration which is more concentrated in the resin composition in the vicinity of the reinforcing fibers than further away. The resin composition comprising a first resin composition impregnates the reinforcing fibers to provide a layer of impregnated reinforcing fibers and a surface layer comprising a second resin composition is formed on the layer of impregnated reinforcing fibers, wherein the first resin composition has at least one peak exotherm occurring at a time earlier than and/or at a temperature lower than any peak exotherm of the second resin composition.

Abstract: Methods of co-bonding a first thermoset composite (TSC) and a second TSC to define a cured composite part are disclosed herein. The methods include partially curing the first TSC to a target state of cure (SOC) to define a first partially cured TSC. The partially curing is based, at least in part, on a maximum temperature of the first TSC during the partially curing and on an elapsed time that an actual temperature of the first TSC is greater than a threshold temperature. The methods further include combining the first partially cured TSC with the second TSC to define a partially cured TSC assembly and heating the partially cured TSC assembly to bond the first partially cured TSC to the second TSC, cure the partially cured TSC assembly, and produce a cured composite part.

Abstract: Systems and methods of curing a thermoset composite (TSC) to a target state of cure (SOC) are disclosed herein. The methods include heating the thermoset composite to greater than a threshold temperature. During the heating, the methods further include monitoring an actual temperature of the thermoset composite, determining a maximum temperature achieved by the thermoset composite, and determining an elapsed time that the actual temperature of the thermoset composite is greater than the threshold temperature. The methods further include ceasing the heating based, at least in part, on the maximum temperature of the TSC and the elapsed time. The systems include a heating assembly, a support mandrel, a thermoset composite, a temperature detector, and a controller programmed to perform the methods.

Abstract: A prepreg comprising a layer of impregnated reinforcing fibers comprising at least one layer of reinforcing fibers impregnated by a resin composition comprising at least a thermosetting resin, a curing agent and an accelerator, such that the accelerator has a gradient concentration which is more concentrated in the resin composition in the vicinity of the reinforcing fibers than further away. The resin composition comprising a first resin composition impregnates the reinforcing fibers to provide a layer of impregnated reinforcing fibers and a surface layer comprising a second resin composition is formed on the layer of impregnated reinforcing fibers, wherein the first resin composition has at least one peak exotherm occurring at a time earlier than and/or at a temperature lower than any peak exotherm of the second resin composition.

Abstract: A fiber reinforced polymer composition is provided comprising a fiber and an adhesive composition, wherein the adhesive composition comprises at least a thermosetting resin, a curing agent, and a hard interfacial material. When cured, the adhesive composition forms good bonds to the reinforcing fiber, and an interfacial region between the reinforcing fiber and the adhesive composition is formed which comprises the hard interfacial material. Additional embodiments include a prepreg and a method of manufacturing a composite article by curing the adhesive composition and the reinforcing fiber.

Abstract: A fiber reinforced polymer composition is provided comprising a fiber and an adhesive composition, wherein the adhesive composition comprises at least a thermosetting resin, a curing agent, and a hard interfacial material. When cured, the adhesive composition forms good bonds to the reinforcing fiber, and an interfacial region between the reinforcing fiber and the adhesive composition is formed which comprises the hard interfacial material. Additional embodiments include a prepreg and a method of manufacturing a composite article by curing the adhesive composition and the reinforcing fiber.

Abstract: A fiber reinforced polymer composition is provided comprising a fiber and an adhesive composition, wherein the adhesive composition comprises at least a thermosetting resin, a curing agent, and an interfacial material comprising a conductive material. When cured the fiber reinforced polymer composition has a z-direction electrical conductivity of at least 1 S/m and the adhesive composition forms good bonds to the reinforcing fiber. An interfacial region between the reinforcing fiber and the adhesive composition comprises the interfacial material. Additional embodiments include a conductive prepreg, a multifunctional prepreg having both load-carrying and non-load carrying functions and a method of manufacturing a composite article by curing the adhesive composition and the reinforcing fiber.

Abstract: A fiber reinforced polymer composition is disclosed comprising a reinforcing fiber and an adhesive composition, wherein the adhesive composition comprises at least a thermosetting resin, a curing agent, and an interfacial material, the fiber is suitable for concentrating the interfacial material in an interfacial region between the fiber and the adhesive composition upon curing of the adhesive composition, and the cured adhesive has a resin modulus of at least 4.0 GPa. Also provided is a prepreg comprising the fiber reinforced polymer composition and a method of manufacturing a composite article by curing the reinforced polymer composition. The resulting interfacial region, viz., the reinforced interphase, is reinforced by one or more layers of the interfacial material such that substantial improvements in tensile, compression and fracture toughness may be observed.

Abstract: A fiber reinforced polymer composition is provided comprising a fiber and an adhesive composition, wherein the adhesive composition comprises at least a thermosetting resin and a curing agent, the reinforcing fiber has a tensile modulus of at least 300 GPa and the cured adhesive has a resin modulus of at least 3.2 GPa, and the adhesive composition when cured makes good bonds to the reinforcing fiber. Additional embodiments include a prepreg comprising the fiber reinforced polymer composition and a method of manufacturing a composite article by curing the adhesive composition and a reinforcing fiber.

Abstract: Embodiments disclosed herein include a structure comprising an adherend and an adhesive composition, wherein the adhesive composition comprises at least a thermosetting resin, a curing agent, and an interfacial material, wherein the adherend is suitable for concentrating the interfacial material in an interfacial region between the adherend and the adhesive composition upon curing of the adhesive composition; a method of manufacturing a composite article by curing the adhesive composition and a reinforcing fiber; and a method of manufacturing an adhesive bonded joint comprising applying the adhesive composition to a surface of one of the two or of different kinds the adherend, and curing the adhesive composition to form an adhesive bond between the adherends. The resulting interfacial region, viz., the reinforced interphase, is reinforced by one or more layers of the interfacial material such that substantial improvements in bond strength and fracture toughness are observed.

Abstract: Embodiments disclosed herein include a resin composition comprising two or more different kinds of thermosetting resins, wherein at least one of the two or more different kinds of the thermosetting resins is a multifunctional resin, and a core-shell particle having a core and a shell, wherein a composition of the core is different from a composition of the shell and the composition of the shell has a branched polymer structure comprising at least one main chain and at least one side chain, the main chain or the side chain containing at least one functional group that reacts with the thermosetting resin, a method of manufacturing the resin composition, and a composite comprising a reinforcing fiber and the resin composition.

Abstract: Core-shell particles and methods of making these particles are described as well as polymer composites comprising these particles. Cores comprise polymerized vinyl monomers and shells comprise polyamine polymers, where the polyamine polymers are covalently attached to the core. Use of these particles in polymer composites, such as epoxies, may impart improved toughness properties to the polymer composites.