The conference consists of a general presentation of plastics and addresses many questions: why so many plastics? How are plastics made? How do we transform plastics into final products? We also question the relationship between the useful properties, the chemical structure and the chemical composition of the mixture used. We are also looking at the origins of monomers and polymerization processes, as well as techniques that improve the performance of plastics.The question of natural polymers and their transformation into plastics usable in everyday life as well as the production of biodegradable polymers from natural or synthetic substances are also addressed. Finally, we tackle the problem of recycling plastics, principle of circular economy and technological advances that will allow us to face the challenges of our society.