There is a tendency to utilize underground space for the less ornamental purposes of civilization; there is the Metropolitan Railway in London, for instance, there are new electric railways, there are subways, there are underground workrooms and restaurants, and they increase and multiply.
Polystyrene can be naturally transparent, but can be colored with colorants. Uses include protective packaging (such as packing peanuts and CD and DVD cases), containers (such as clamshells), lids, bottles, trays, tumblers, and disposable cutlery.
Thermoplastic resins are most commonly unreinforced, meaning, the resin is formed into shapes and have no reinforcement providing strength. Examples of common thermoplastic resins used today, and products manufactured with them include: 1  PET-Water and soda bottles. 2  Polyproplyene-Packaging containers. 3  Polycarbonate-Safety glass lenses. 4  PBT-Children's Toys. 5  Vinyl-Window frames. 6  Polyethlene-Grocery bags. 7  PVC-Piping.