Encapsulation Compound
Rigid thermosetting polymer compounds encapsulate delicate optical and electronic components to isolate them from environmental ingress and mechanical vibrations. An epoxy potting encapsulant provides mechanical structural support while sealing optical fiber feedthroughs and sensor housings against fluid exposure.
Thermal Strain
Differential thermal expansion between encapsulating polymers and silica optical fibers introduces mechanical stress during thermal cycling. As an epoxy potting encapsulant cures, volumetric shrinkage generates residual compressive forces directly onto embedded glass fibers. Exothermic curing reaction heat elevates internal assembly temperatures, causing localized stress concentration upon cooling.
Formulations with low thermal expansion coefficients minimize microbending attenuation in optical fiber sensors.
Moisture Ingress
Long-term exposure to ambient humidity results in water absorption by the polymer matrix. Absorbed moisture lowers the glass transition temperature of the cured resin and causes plasticization.
Sourcing Specification
Procurement requirements specify curing temperature schedules, outgassing rates and glass transition temperature limits verified according to ASTM E595 testing standards. Glass transition temperatures must exceed maximum operating thermal limits to maintain dimensional stability during continuous deployment. Hardness testing using Shore D durometer scales confirms full polymer cross-linking across production batches.
Encapsulated optical sensors failing outgassing limits risk optical window contamination in vacuum or high-reliability applications.
