Q. What do you mean by Thermosetting plastics?

This plastic undergoes a number of chemical changes on heating and cure to infusible and practically insoluble articles. The chemical change is not reversible thermosetting plastics do not soften on reheating and can not be reworked. They rather become harder due to completion of any left-over polymerization reaction. Eventually, at high temperatures, the useful properties of the plastic get destroyed. This is called degradation. The commonest thermosetting plastics are: alkyds, epoxides, polyesters, phenolics and urea.