Plastic Engineering (Diploma / Polytechnic) Interview Questions & Answers — commonly asked polytechnic diploma interview and campus placement questions with clear, practical answers. Tap any question to open its answer. Showing the first 50 questions free. The complete 250-question bank is available as a PDF below. Plastic Engineering — Diploma Interview Q&A Q1 What is Plastic Engineering? Answer Plastic Engineering is the branch of engineering that deals with the development, processing, testing, and application of plastic and polymer materials. It covers polymer science, injection molding, extrusion, blow molding, compression molding, plastic product design, material testing, and recycling. Q2 What is a polymer? Answer A polymer is a large molecule made by joining many smaller repeating molecules called monomers through a process known as polymerization. Polymers can be natural or synthetic and form the basic materials used in plastics, rubber, fibers, and many eng...