Effects of Hydrophobic Barrier Films on the Mechanical Properties of Fiber Reinforced Composites Immersed in Water

Abstract

Fiber reinforced composites are subjected to a wide range of mechanical loads and environmental conditions, such as wind, high/low temperature, moisture, UV light and aggressive solvents. Compared to other structural materials, polymers can absorb more moisture and UV light from outside environment and lose their material properties (e.g., mechanical, electrical, surface and thermal) and thus the service life. In this study, hydrophobic barrier films including polyvinylfluoride (PVF) and polyether ether ketone (PEEK) were applied on the carbon, Kevlar, and glass fiber reinforced epoxy resin composites (laminate and sandwich structures), and then the effects of moisture absorption on those films were investigated in detail. The coupons were immersed in water for a number of days in order to determine the changes in mechanical properties of the composites. Three point bending tests were applied to the laminate composites, while four point bending tests were conducted on the Nomex sandwich structured composites. We found that moisture absorption could be eliminated by using these hydrophobic films. We found that PEEK film could be an alternative barrier film for the aircraft industry.

Effects of moisture ingressions on mechanical properties of honeycomb-structured fiber composites for aerospace applications

“…During service, honeycomb-structured polymeric composites are subjected to a wide range of mechanical loads and environmental conditions, such as high and low temperatures, moisture, hydraulic fluids, and other solvents [20][21][22][23][24][25][26][27]. When compared to other structural materials, polymeric materials can absorb more water, hydraulic fluids, and solvents from internal and external sources into their structures.…”

Investigations of moisture ingressions in composites via NDI techniques

“…Different NDI techniques have been reported for their effectiveness in detecting, sizing and depth evaluation. Each technique has their advantages and drawbacks [9][10][11][12][13][14][15][16][17]. In this study, we tried to evaluate a procedure to report the presence of moisture, which may be useful for the future developments in the field.…”