Reversible dielectric property degradation in moisture-contaminated fiber-reinforced laminates

Luis A. Rodriguez, Carla García, Mauro Fittipaldi, Landon R. Grace

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The potential for recovery of dielectric properties of three water-contaminated fiber-reinforced laminates is investigated using a split-post dielectric resonant technique at X-band (10 GHz). The three material systems investigated are bismaleimide (BMI) reinforced with an eight-harness satin weave quartz fabric, an epoxy resin reinforced with an eight- harness satin weave glass fabric (style 7781), and the same epoxy reinforced with a four-harness woven glass fabric (style 4180). A direct correlation between moisture content, dielectric constant, and loss tangent was observed during moisture absorption by immersion in distilled water at 25 °C for five equivalent samples of each material system. This trend is observed through at least 0.72% water content by weight for all three systems. The absorption of water into the BMI, 7781 epoxy, and 4180 epoxy laminates resulted in a 4.66%, 3.35%, and 4.01% increase in dielectric constant for a 0.679%, 0.608%, and 0.719% increase in water content by weight, respectively. Likewise, a significant increase was noticed in loss tangent for each material. The same water content is responsible for a 228%, 71.4%, and 64.1% increase in loss tangent, respectively. Subsequent to full desorption through drying at elevated temperature, the dielectric constant and loss tangent of each laminate exhibited minimal change from the dry, pre-absorption state. The dielectric constant and loss tangent change after the absorption and desorption cycle, relative to the initial state, was 0.144 % and 2.63% in the BMI, 0.084% and 1.71% in the style 7781 epoxy, and 0.003% and 4.51% in the style 4180 epoxy at near-zero moisture content. The similarity of dielectric constant and loss tangent in samples prior to absorption and after desorption suggests that any chemical or morphological changes induced by the presence of water have not caused irreversible changes in the dielectric properties of the laminates.

Original languageEnglish (US)
Title of host publicationProceedings of PPS 2015
Subtitle of host publicationThe 31st International Conference of the Polymer Processing Society - Conference Papers
EditorsByungohk Rhee
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735413603
StatePublished - Mar 9 2016
Event31st International Conference of the Polymer Processing Society, PPS 2015 - Jeju Island, Korea, Republic of
Duration: Jun 7 2015Jun 11 2015

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other31st International Conference of the Polymer Processing Society, PPS 2015
Country/TerritoryKorea, Republic of
CityJeju Island


  • Dielectric constant
  • Loss Tangent

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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