Weight Gain Data Under Cyclic Exposure

Credit Delasi, R.., and Schulte, R. L. Moisture Detection in Composites Using Nuclear Reaction Analysis. 13(4), pp. 303-310, copyright 1979 by Journal of Composite Materials. 

Distributions of H2SO4 and HCl across a protective polymeric layer at various times, temperatures, and concentrations are shown in Figs. 4.16 and 4.17. Note, however that the concentration fronts are somewhat slanting and not perfectly sharp (Figs. 4.14 and 4.15). 

8 Weight Gain Data Under Cyclic Exposure 

Typical absorption/desorption data for uni-directionally reinforced AS4/3502 coupons, exposed to RH = 97% to saturation and subsequently to RH = 0%, all at r = 40°C, are shown in Fig 4.16 below (desorption data are plotted in a reverse direction) 

Note the hysteresis loop between the two data sets. The observation that desorption starts at a faster rate than absorption is consistent with results such as shown in Table 4.2. 

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