Damage to Composites from Electrochemical Processes

Recycling of carbon fibers from carbon fiber reinforced polymer using electrochemical method

“…Finally, when the current increased to 25 mA, much more OH À generated on the surface of the CFRP anode with blisters formed. The pH of these blisters as reported in literature is in between 10 and 11 [24], which do not dissolve the polymer but forms a protective layer to reduce the contact by destructive OCl À . Thus, less epoxy was removed when compared to I20 group, although current increased.…”

Corrosive delamination processes of CFRP‐aluminum alloy hybrid components

“…Therefore, the authors suggest that the blisters only develop in correlation with the glass fibers (source of water soluble molecules) near the surface. Comparable studies are presented in Refs …”

“…Comparable studies are presented in Refs. [12,23,25] The development of the pH value as a result of the local cathodic reaction was monitored on a CFRP-aluminum hybrid specimen. After 2 min an alkalization in the overlap FIGURE 5 Visual changes of the CFRP surface in the overlap region FIGURE 6 Breaking/buckling of the glass fibers (left) and debonding between the glass fibers and the epoxy matrix (right) as observed by FIB FE-SEM area could be observed (pink coloring of the indicator phenolphthalein).…”

Galvanically Stimulated Degradation of Carbon-Fiber Reinforced Polymer Composites: A Critical Review

“…The pre-treatment of carbon fiber surfaces by oxidative methods which is reported [ 173 ] to improve fiber/resin adhesion have serious implications on the electrochemical reactivity and chemical stability of CFRP under cathodic polarization, as oxidized carbon surfaces have been reported by Taylor and Humffray [ 204 ] to result in oxygen reduction to OH − instead of peroxide in alkaline media (pH > 10). This scenario is likely to lead to less degradation of the polymer matrix in CFRP composites containing carbon fibers that have been pre-treated in an oxygen environment prior to exposure to cathodic polarizations, as the presence of hydroxyl and peroxide ions are reported to enhance ring opening reactions in polymer matrices [ 205 , 206 , 207 , 208 ].…”

“…In addition to the mechanism summarized above, Taylor et al [ 343 ] postulated from their results that although hydroxyl ions were regarded to be the damaging species, the superoxide radicals produced during homogeneous peroxide decomposition can be the major deleterious species owing to their ability to react with labile hydrogens on the polymer surface to produce the even more highly reactive hydroperoxyl radical (HOO*) which being hydrocarbon soluble can readily diffuse through the polymer matrix in which its further reaction with labile hydrogen produces peroxide [ 344 ]. Damage to the polymer matrix due to cathodic polarization is reportedly marked in polymer composites with polymer matrices that are capable of ring opening reactions in the presence of hydroxyl and peroxide ions [ 205 , 206 , 207 , 208 ].…”