This is a first study comparing dielectric spectroscopy and gravimetric measurements of moisture uptake in pultruded glass fibre reinforced polymers (FRPs). Specimens were subjected to sub-Tg hygrothermal aging for 224 days. Impedance spectra in the frequency range 0.1 Hz to 10 MHz were captured during exposure and compared with gravimetric measurements. Moisture concentration was found to increase the FRP’s dielectric permittivity monotonically and decrease bulk resistance. High quality dielectric data was obtained as moisture uptake is independent of inherent changes suggested by mass loss which compromise gravimetry. Dielectric measurements remained sensitive to moisture despite significant mass loss, which typically distorts the weight gain process complicating the commonly adopted gravimetric methodology. Real-time dielectric measurements were obtained from FRP specimens continuously immersed in water and without making use of any additional sensing elements. The novel approach adopted is of high commercial impact as moisture uptake control is recognized as a significant problem by industry.

这是第一项比较拉挤玻璃纤维增​​强聚合物（FRP）中介电谱和重量法测量水分吸收的研究。样品经受亚Tg湿热老化224天。在曝光过程中捕获了0.1 Hz至10 MHz频率范围内的阻抗谱，并与重量分析法进行了比较。发现水分浓度单调增加了FRP的介电常数并降低了体电阻。获得了高质量的介电数据，因为水分的吸收与质量损失所暗示的固有变化无关，质量变化会损害重量分析法。尽管质量损失很大，但介电测量值仍然对水分敏感，这通常会使增重过程失真，使通常采用的重量分析方法复杂化。实时介电测量是从连续浸入水中的FRP样品获得的，无需使用任何其他传感元件。所采用的新颖方法具有很高的商业影响，因为水分吸收控制已被业界认为是一个重大问题。