The investigation on the curing process of polysulfide sealant by in situ dielectric analysis

Abstract

In this work, in situ dielectric analysis (DEA) was employed for the first time to the best of our knowledge, to monitor the curing process of polysulfide (PSF) sealant using manganese dioxide (MnO 2 ) as the curing agent, where the gel point and ending point were determined. The obtained results were verified by rheological tests of dynamic mechanical analysis and tensile strength tests. It showed a significant difference between this curing process and those of usual thermosetting materials. The influences of the pH value of the samples and curing temperature were investigated and discussed in detail. Also, activation energies of the curing reaction of the samples with different pH values were calculated. The results proved DEA as a reliable and useful method for in situ monitoring PSF-MnO 2 curing process.

Self-Healable and Reprocessable Polysulfide Sealants Prepared from Liquid Polysulfide Oligomer and Epoxy Resin

“…Because of their lower cost, excellent adhesion, good low-temperature property, low water-vapor permeability as well as high resistance to UV radiation and environmental degradation, polysulfide sealants have a wide range of industrial applications . Thiol-terminated polysulfide oligomers are most commonly used in the preparation of polysulfide sealants because of their highly reactive terminal mercaptans, which can be easily converted into polymeric networks by oxidation or using other active groups, such as epoxy, isocyanate, and vinyl. − To date, the curing kinetic analysis, mechanical properties, compression behavior, thermal stability, and photodegradation process of the polysulfide sealants have been studied extensively. However, to the best of our knowledge, the self-healing and reprocessing abilities of the polysulfide sealants have not yet been investigated.…”

Processing

“…Examples range from various epoxy systems [45,46,65À67] or unsaturated polyesters [1] to aminoplastic wood adhesives [68] and polysulfide based sealants [69]. Dielectric Analysis (DEA), according to ASTM E 2038 and E 2039, measures the changes in the dielectric properties of a thermosetting resin that take place during the cross-linking process.…”

Blocking of Fuel Filter in Aircraft by an Accelerator Blooming

“…Polysulfide polymers with the terminal thiol end groups were cured by the oxidation of two end thiol groups in the presence of MnO 2 . [8][9][10][11][12][13][14] As a result, disulfide bond was formed. The curing process can be simply described with eq.…”