Polymer engineering deals with design analysis and modification of polymer materials. Basically it covers areas of petrochemical industry, polymerization, compounding and description and properties of polymers.
Polymers are basically divided into theromsets and thermoplastics and these engineers work with various polymers and their composite materials or various types of applications. They find application in various things that range from aircrafts to medical equipments to fishing rods etc.
Plastic engineering is sub part of polymer engineering as plastic is essentially a polymeric material. In polymer engineering the economics of polymer plays a very crucial role as they have to create a product with desired specifications and qualities but keeping the cost low.