Thermosetting polymers like Bakelite and Melamine-formaldehyde resin become permanently infusible an — Polymers Chemistry Question
Question
Thermosetting polymers like Bakelite and Melamine-formaldehyde resin become permanently infusible and insoluble upon their initial heating in a mold. From a mechanistic standpoint, which fundamental chemical process is responsible for this irreversible change?
💡 Solution & Explanation
Thermosetting polymers are heavily branched prepolymers. Heating them in a mold provides the activation energy needed to form extensive covalent chemical bonds (cross-links) between the chains. This transforms the material into a single, giant 3D network molecule that cannot melt or dissolve without breaking chemical bonds (decomposing).