Which statement best describes polymer degradation as presented?

• A. They do not corrode; they undergo physicochemical degradation.
• B. Covalent bonds rupture by swelling and dissolution, with solute atoms diffusing through the polymer.
• C. Degradation occurs only by mechanical wear.
• D. Polymers form protective oxide layers during degradation.

Answer: (A)

Polymer degradation is a chemical and physical aging process driven by environmental stresses such as heat, light, oxygen, moisture, or chemicals. It involves changes like chain scission, oxidation, hydrolysis, and physical alterations (e.g., plasticization or crazing) that weaken the material over time. Metals corrode through electrochemical reactions that form protective oxide films or soluble products; polymers don’t typically undergo corrosion in that sense. Instead, their degradation is best described as a physicochemical process because it combines chemical reactions with physical changes without relying on metal-like electrochemical corrosion.

This makes the statement that best describes polymer degradation: polymers do not corrode; they undergo physicochemical degradation. It captures the idea that degradation is not simply mechanical wear or a specific oxide-layer formation, and it isn’t correctly described as bonds rupturing purely due to swelling and dissolution with diffusion of solutes.