Curable sealant compositions comprise the components: a) x weight percent of at least one polythiol; b) y weight percent of at least one unsaturated compound having at least two non-aromatic carbon-carbon double bonds, at least one carbon-carbon triple bond, or a combination thereof; c) from 0.01 to 8 weight percent of at least one quaternary ammonium or phosphonium salt; d) from 0.05 to 10 weight percent of at least one organic peroxide; and e) optionally from 0.01 to 10 weight percent of a photoinitiator system capable of generating free radicals upon exposure to actinic radiation. Each of x and y represents a positive real number. The sum x+y is in the range of 72 to 99. The weight percent ranges of the components a)-e) are based on the total weight of the components a)-e). A seal cap including the curable sealant composition and methods of making and using the curable sealant compositions are also disclosed.

Curable sealant compositions comprise the components: a) x weight percent of at least one polythiol; b) y weight percent of at least one unsaturated compound having at least two non-aromatic carbon-carbon double bonds, at least one carbon-carbon triple bond, or a combination thereof; c) from 0.01 to 8 weight percent of at least one quaternary ammonium or phosphonium salt; d) from 0.05 to 10 weight percent of at least one organic peroxide; and e) optionally from 0.01 to 10 weight percent of a photoinitiator system capable of generating free radicals upon exposure to actinic radiation. Each of x and y represents a positive real number. The sum x+y is in the range of 72 to 99. The weight percent ranges of the components a)-e) are based on the total weight of the components a)-e). A seal cap including the curable sealant composition and methods of making and using the curable sealant compositions are also disclosed.

A composition includes a photolatent amine, camphorquinone, and a coumarin sensitizer. The coumarin sensitizer is triplet photosensitizer and has an absorbance with a wavelength of maximum absorbance in a range from 390 nanometers to 510 nanometers. Compositions that further include a polymerizable material are also disclosed. Polymer networks preparable from such compositions and methods for making the polymer networks are also disclosed.

A composition includes a photolatent amine, camphorquinone, and a coumarin sensitizer. The coumarin sensitizer is triplet photosensitizer and has an absorbance with a wavelength of maximum absorbance in a range from 390 nanometers to 510 nanometers. Compositions that further include a polymerizable material are also disclosed. Polymer networks preparable from such compositions and methods for making the polymer networks are also disclosed.

Compositions that are curable to polythioether polymers are provided, comprising: a) a dithiol monomer; b) a diene monomer; c) a radical cleaved photoinitiator; d) a peroxide; and e) an amine; where the peroxide and amine together are a peroxide-amine redox initiator. In some embodiments, the amine is a tertiary amine. In some embodiments, the amine is selected from the group consisting of dihydroxyethyl-p-toluidine, N,N-diisopropylethylamine, and N, N, N′, N″, N″-pentamethyl-diethylenetriamine. In some embodiments, the peroxide is selected from the group consisting of di-tert-butyl peroxide, methyl ethyl ketone peroxide, and benzoyl peroxide. In some embodiments, the composition may additionally comprise a polythiol monomer having three or more thiol groups.

Compositions that are curable to polythioether polymers are provided, comprising: a) a dithiol monomer; b) a diene monomer; c) a radical cleaved photoinitiator; d) a peroxide; and e) an amine; where the peroxide and amine together are a peroxide-amine redox initiator. In some embodiments, the amine is a tertiary amine. In some embodiments, the amine is selected from the group consisting of dihydroxyethyl-p-toluidine, N,N-diisopropylethylamine, and N, N, N′, N″, N″-pentamethyl-diethylenetriamine. In some embodiments, the peroxide is selected from the group consisting of di-tert-butyl peroxide, methyl ethyl ketone peroxide, and benzoyl peroxide. In some embodiments, the composition may additionally comprise a polythiol monomer having three or more thiol groups.

Low density aerospace compositions and sealants are disclosed. The low density compositions and sealants are characterized by a high volume percent loading of low density microcapsules.

Low density aerospace compositions and sealants are disclosed. The low density compositions and sealants are characterized by a high volume percent loading of low density microcapsules.

Adhesion-promoting compositions and the use of the adhesion-promoting compositions to provide adhesion-promoting interlayers to enhance adhesion between adjoining layers of sulfur-containing sealants are disclosed. In repair applications, the adhesion-promoting compositions can enhance the adhesion of an overlying radiation-curable sulfur-containing sealant to a damaged or aged sulfur-containing sealant.

Disclosed is a photocurable composition containing a dithiol compound having a disulfide bond, a compound having two ethylenically unsaturated groups, a hydrogen abstraction type photoradical generator, and an intramolecular cleavage type photoradical generator.