Characterization of a non-destructive microwave technique for the detection and quantification of water in thermosets and thermoplastics

• An open-ended microwave resonator is proposed for detecting water in polymers.
• It was possible to quantify the moisture content in epoxy and polyamide-6.
• We reported the penetration depth of the standing microwave through epoxy (~24 mm).
• The penetration depth of the microwaves through polyamide-6 is at least of 7.35 mm.
• It is reported the suitability of this device as contactless non-destructive technique.

In this paper, the detection and quantification of the moisture content in epoxy and polyamide-6 using a non-destructive and portable device based on a microwave resonator technique is reported. Parameters related to the real (ε′ε′) and imaginary (ε″ε″) part of the complex permittivity were used to quantify the moisture content in these polymers. The maximal penetration and analyzing depth of the microwaves through polyamide-6 (both at least of 7.35 mm) and epoxy (24 mm and 12 mm, respectively) were measured performing samples with different thicknesses. Moreover, measurements were performed at different distances from the sample surface being possible to perform contactless measurements.