Abstract:
Polymeric coating materials have been used for decades to protect various substrates from
degradation, such as corrosion, which can cause failure of important aspects in vehicles
and buildings. The proper removal of polymeric coating materials is as important as their
protection of underlying substrates since improper removal will damage the substrate.
Methylene chloride and phenol based removers have been utilized for this purpose for over
50 years. During which time little understanding of the mechanism for the degradation of
polymeric materials from these solvents has been developed. This work employed two
military polyurethane coatings in three different formulations: full, partial and clear.
Simplified formulations and control mixtures of solvents commonly used in methylene
chloride and phenol removers were developed in order to deconvolute analysis of the
complex polymeric material and the solvent systems. The polymeric coatings were
exposed to the different solvents and solvent solutions. Analyses were conducted utilizing
multiple techniques to determine the mechanism for the degradation of polymeric coatings. These analyses revealed that methylene chloride solvated and swelled the coating while
phenol degraded the polymer by nucleophilic attack. It was also determined that the
addition of water to the solution significantly increased degradation. The enhanced
degradation arose from the water molecule abstracting the proton from phenol, which
increased its nucleophilicity.
